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Have you ever wondered about the mechanisms that delivered this page to you? Chances are you are sitting at a computer right now, viewing this page in a browser. So, when you clicked on the link for this page, or typed in its URL (uniform resource locator), what happened behind the scenes to bring this page onto your screen? If you've ever been curious about the process, or have ever wanted to know some of the specific mechanisms that allow you to surf the Internet, then read on. In this article, you will learn how Web servers bring pages into your home, school or office. Let's get started!



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Let's say that you are sitting at your computer, surfing the Web, and you get a call from a friend who says, "I just read a great article! Type in this URL and check it out. It's at http://www.howstuffworks.com/web-server.htm." So you type that URL into your browser and press return. And magically, no matter where in the world that URL lives, the page pops up on your screen.
At the most basic level possible, the following diagram shows the steps that brought that page to your screen:

Your browser formed a connection to a Web server, requested a page and received it.
On the next page, we'll dig a bit deeper.


If you want to get into a bit more detail on the process of getting a Web page onto your computer screen, here are the basic steps that occurred behind the scenes:

• The browser broke the URL into three parts:
  
  1. The protocol ("http")
  2. The server name ("www.howstuffworks.com")
  3. The file name ("web-server.htm")
• The browser communicated with a name server to translate the server name "www.howstuffworks.com" into an IP Address, which it uses to connect to the server machine.
• The browser then formed a connection to the server at that IP address on port 80. (We'll discuss ports later in this article.)
• Following the HTTP protocol, the browser sent a GET request to the server, asking for the file "http://www.howstuffworks.com/web-server.htm." (Note that cookies may be sent from browser to server with the GET request -- see How Internet Cookies Work for details.)
• The server then sent the HTML text for the Web page to the browser. (Cookies may also be sent from server to browser in the header for the page.)
• The browser read the HTML tags and formatted the page onto your screen.

If you've never explored this process before, that's a lot of new vocabulary. To understand this whole process in detail, you need to learn about IP addresses, ports, protocols... The following sections will lead you through a complete explanation.

So what is "the Internet"? The Internet is a gigantic collection of millions of computers, all linked together on a computer network. The network allows all of the computers to communicate with one another. A home computer may be linked to the Internet using a phone-line modem, DSL or cable modem that talks to an Internet service provider (ISP). A computer in a business or university will usually have a network interface card (NIC) that directly connects it to a local area network (LAN) inside the business. The business can then connect its LAN to an ISP using a high-speed phone line like a T1 line. A T1 line can handle approximately 1.5 million bits per second, while a normal phone line using a modem can typically handle 30,000 to 50,000 bits per second. ISPs then connect to larger ISPs, and the largest ISPs maintain fiber-optic "backbones" for an entire nation or region. Backbones around the world are connected through fiber-optic lines, undersea cables or satellite links (see An Atlas of Cyberspaces for some interesting backbone maps). In this way, every computer on the Internet is connected to every other computer on the Internet.



In general, all of the machines on the Internet can be categorized as two types: servers and clients. Those machines that provide services (like Web servers or FTP servers) to other machines are servers. And the machines that are used to connect to those services are clients. When you connect to Yahoo! at www.yahoo.com to read a page, Yahoo! is providing a machine (probably a cluster of very large machines), for use on the Internet, to service your request. Yahoo! is providing a server. Your machine, on the other hand, is probably providing no services to anyone else on the Internet. Therefore, it is a user machine, also known as a client. It is possible and common for a machine to be both a server and a client, but for our purposes here you can think of most machines as one or the other. A server machine may provide one or more services on the Internet. For example, a server machine might have software running on it that allows it to act as a Web server, an e-mail server and an FTP server. Clients that come to a server machine do so with a specific intent, so clients direct their requests to a specific software server running on the overall server machine. For example, if you are running a Web browser on your machine, it will most likely want to talk to the Web server on the server machine. Your Telnet application will want to talk to the Telnet server, your e-mail application will talk to the e-mail server, and so on...


To keep all of these machines straight, each machine on the Internet is assigned a unique address called an IP address. IP stands for Internet protocol, and these addresses are 32-bit numbers, normally expressed as four "octets" in a "dotted decimal number." A typical IP address looks like this:

216.27.61.137

The four numbers in an IP address are called octets because they can have values between 0 and 255, which is 2⁸ possibilities per octet.
Every machine on the Internet has a unique IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP address that is assigned by the ISP when the machine dials in. That IP address is unique for that session -- it may be different the next time the machine dials in. This way, an ISP only needs one IP address for each modem it supports, rather than for each customer.
If you are working on a Windows machine, you can view a lot of the Internet information for your machine, including your current IP address and hostname, with the command WINIPCFG.EXE (IPCONFIG.EXE for Windows 2000/XP). On a UNIX machine, type nslookup at the command prompt, along with a machine name, like www.howstuffworks.com -- e.g. "nslookup www.howstuffworks.com" -- to display the IP address of the machine, and you can use the command hostname to learn the name of your machine. (For more information on IP addresses, see IANA.)
As far as the Internet's machines are concerned, an IP address is all you need to talk to a server. For example, in your browser, you can type the URL http://209.116.69.66 and arrive at the machine that contains the Web server for HowStuffWorks. On some servers, the IP address alone is not sufficient, but on most large servers it is -- keep reading for details.


Because most people have trouble remembering the strings of numbers that make up IP addresses, and because IP addresses sometimes need to change, all servers on the Internet also have human-readable names, called domain names. For example, www.howstuffworks.com is a permanent, human-readable name. It is easier for most of us to remember www.howstuffworks.com than it is to remember 209.116.69.66. The name www.howstuffworks.com actually has three parts:

1. The host name ("www")
2. The domain name ("howstuffworks")
3. The top-level domain name ("com")

Domain names within the ".com" domain are managed by the registrar called VeriSign. VeriSign also manages ".net" domain names. Other registrars (like RegistryPro, NeuLevel and Public Interest Registry) manage the other domains (like .pro, .biz and .org). VeriSign creates the top-level domain names and guarantees that all names within a top-level domain are unique. VeriSign also maintains contact information for each site and runs the "whois" database. The host name is created by the company hosting the domain. "www" is a very common host name, but many places now either omit it or replace it with a different host name that indicates a specific area of the site. For example, in encarta.msn.com, the domain name for Microsoft's Encarta encyclopedia, "encarta" is designated as the host name instead of "www."

The whois Command On a UNIX machine, you can use the whois command to look up information about a domain name. You can do the same thing using the whois form at VeriSign. If you type in a domain name, like "howstuffworks.com," it will return to you the registration information for that domain, including its IP address.

A set of servers called domain name servers (DNS) maps the human-readable names to the IP addresses. These servers are simple databases that map names to IP addresses, and they are distributed all over the Internet. Most individual companies, ISPs and universities maintain small name servers to map host names to IP addresses. There are also central name servers that use data supplied by VeriSign to map domain names to IP addresses. If you type the URL "http://www.howstuffworks.com/web-server.htm" into your browser, your browser extracts the name "www.howstuffworks.com," passes it to a domain name server, and the domain name server returns the correct IP address for www.howstuffworks.com. A number of name servers may be involved to get the right IP address. For example, in the case of www.howstuffworks.com, the name server for the "com" top-level domain will know the IP address for the name server that knows host names, and a separate query to that name server, operated by the HowStuffWorks ISP, may deliver the actual IP address for the HowStuffWorks server machine.
On a UNIX machine, you can access the same service using the nslookup command. Simply type a name like "www.howstuffworks.com" into the command line, and the command will query the name servers and deliver the corresponding IP address to you.
So here it is: The Internet is made up of millions of machines, each with a unique IP address. Many of these machines are server machines, meaning that they provide services to other machines on the Internet. You have heard of many of these servers: e-mail servers, Web servers, FTP servers, Gopher servers and Telnet servers, to name a few. All of these are provided by server machines.


Any server machine makes its services available to the Internet using numbered ports, one for each service that is available on the server. For example, if a server machine is running a Web server and an FTP server, the Web server would typically be available on port 80, and the FTP server would be available on port 21. Clients connect to a service at a specific IP address and on a specific port. Each of the most well-known services is available at a well-known port number. Here are some common port numbers:

• echo 7
• daytime 13
• qotd 17 (Quote of the Day)
• ftp 21
• telnet 23
• smtp 25 (Simple Mail Transfer, meaning e-mail)
• time 37
• nameserver 53
• nicname 43 (Who Is)
• gopher 70
• finger 79
• WWW 80

If the server machine accepts connections on a port from the outside world, and if a firewall is not protecting the port, you can connect to the port from anywhere on the Internet and use the service. Note that there is nothing that forces, for example, a Web server to be on port 80. If you were to set up your own machine and load Web server software on it, you could put the Web server on port 918, or any other unused port, if you wanted to. Then, if your machine were known as xxx.yyy.com, someone on the Internet could connect to your server with the URL http://xxx.yyy.com:918. The ":918" explicitly specifies the port number, and would have to be included for someone to reach your server. When no port is specified, the browser simply assumes that the server is using the well-known port 80.

Once a client has connected to a service on a particular port, it accesses the service using a specific protocol. The protocol is the pre-defined way that someone who wants to use a service talks with that service. The "someone" could be a person, but more often it is a computer program like a Web browser. Protocols are often text, and simply describe how the client and server will have their conversation. Perhaps the simplest protocol is the daytime protocol. If you connect to port 13 on a machine that supports a daytime server, the server will send you its impression of the current date and time and then close the connection. The protocol is, "If you connect to me, I will send you the date and time and then disconnect." Most UNIX machines support this server. If you would like to try it out, you can connect to one with the Telnet application. In UNIX, the session would look like this:

%telnet web67.ntx.net 13
Trying 216.27.61.137...
Connected to web67.ntx.net.
Escape character is '^]'.
Sun Oct 25 08:34:06 1998
Connection closed by foreign host.

On a Windows machine, you can access this server by typing "telnet web67.ntx.net 13" at the MSDOS prompt.
In this example, web67.ntx.net is the server's UNIX machine, and 13 is the port number for the daytime service. The Telnet application connects to port 13 (telnet naturally connects to port 23, but you can direct it to connect to any port), then the server sends the date and time and disconnects. Most versions of Telnet allow you to specify a port number, so you can try this using whatever version of Telnet you have available on your machine.
Most protocols are more involved than daytime and are specified in Request for Comment (RFC) documents that are publicly available (see http://sunsite.auc.dk/RFC/ for a nice archive of all RFCs). Every Web server on the Internet conforms to the HTTP protocol, summarized nicely in The Original HTTP as defined in 1991. The most basic form of the protocol understood by an HTTP server involves just one command: GET. If you connect to a server that understands the HTTP protocol and tell it to "GET filename," the server will respond by sending you the contents of the named file and then disconnecting. Here's a typical session:

%telnet www.howstuffworks.com 80
Trying 216.27.61.137...
Connected to howstuffworks.com.
Escape character is '^]'.
GET http://www.howstuffworks.com/



  ...


Connection closed by foreign host.

In the original HTTP protocol, all you would have sent was the actual filename, such as "/" or "/web-server.htm." The protocol was later modified to handle the sending of the complete URL. This has allowed companies that host virtual domains, where many domains live on a single machine, to use one IP address for all of the domains they host. It turns out that hundreds of domains are hosted on 209.116.69.66 -- the HowStuffWorks IP address.


Now you know a tremendous amount about the Internet. You know that when you type a URL into a browser, the following steps occur:

• The browser breaks the URL into three parts:
  
  1. The protocol ("http")
  2. The server name ("www.howstuffworks.com")
  3. The file name ("web-server.htm")
• The browser communicates with a name server to translate the server name, "www.howstuffworks.com," into an IP address, which it uses to connect to that server machine.
• The browser then forms a connection to the Web server at that IP address on port 80.
• Following the HTTP protocol, the browser sends a GET request to the server, asking for the file "http://www.howstuffworks.com/web-server.htm." (Note that cookies may be sent from browser to server with the GET request -- see How Internet Cookies Work for details.)
• The server sends the HTML text for the Web page to the browser. (Cookies may also be sent from server to browser in the header for the page.)
• The browser reads the HTML tags and formats the page onto your screen.

You can see from this description that a Web server can be a pretty simple piece of software. It takes the file name sent in with the GET command, retrieves that file and sends it down the wire to the browser. Even if you take into account all of the code to handle the ports and port connections, you could easily create a C program that implements a simple Web server in less than 500 lines of code. Obviously, a full-blown enterprise-level Web server is more involved, but the basics are very simple. Most servers add some level of security to the serving process. For example, if you have ever gone to a Web page and had the browser pop up a dialog box asking for your name and password, you have encountered a password-protected page. The server lets the owner of the page maintain a list of names and passwords for those people who are allowed to access the page; the server lets only those people who know the proper password see the page. More advanced servers add further security to allow an encrypted connection between server and browser, so that sensitive information like credit card numbers can be sent on the Internet.
That's really all there is to a Web server that delivers standard, static pages. Static pages are those that do not change unless the creator edits the page.


But what about the Web pages that are dynamic? For example:

• Any guest book allows you to enter a message in an HTML form, and the next time the guest book is viewed, the page will contain the new entry.
• The whois form at Network Solutions allows you to enter a domain name on a form, and the page returned is different depending on the domain name entered.
• Any search engine lets you enter keywords on an HTML form, and then it dynamically creates a page based on the keywords you enter.

In all of these cases, the Web server is not simply "looking up a file." It is actually processing information and generating a page based on the specifics of the query. In almost all cases, the Web server is using something called CGI scripts to accomplish this feat. CGI scripts are a topic unto themselves, and are described in the HowStuffWorks article How CGI Scripting Work.

If you spend any time on the Internet sending e-mail or browsing the Web, then you use domain name servers without even realizing it. Domain name servers, or DNS, are an incredibly important but completely hidden part of the Internet, and they are fascinating. The DNS system forms one of the largest and most active distributed databases on the planet. Without DNS, the Internet would shut down very quickly.
In this article, we'll take a look at the DNS system so you can understand how it works and appreciate its amazing capabilities.
When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL "http://www.howstuffworks.com" contains the domain name howstuffworks.com. So does the e-mail address "iknow@howstuffworks.com."
Human-readable names like "howstuffworks.com" are easy for people to remember, but they don't do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "www.howstuffworks.com" has the IP address 70.42.251.42. Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address. During a day of browsing and e-mailing, you might access the domain name servers hundreds of times!
Domain name servers translate domain names to IP addresses. That sounds like a simple task, and it would be -- except for five things:

• There are billions of IP addresses currently in use, and most machines have a human-readable name as well.
• There are many billions of DNS requests made every day. A single person can easily make a hundred or more DNS requests a day, and there are hundreds of millions of people and machines using the Internet daily.
• Domain names and IP addresses change daily.
• New domain names get created daily.
• Millions of people do the work to change and add domain names and IP addresses every day.

The DNS system is a database, and no other database on the planet gets this many requests. No other database on the planet has millions of people changing it every day, either. That is what makes the DNS system so unique.

IP Addresses
To keep all of the machines on the Internet straight, each machine is assigned a unique address called an IP address. IP stands for Internet protocol, and these addresses are 32-bit numbers normally expressed as four "octets" in a "dotted decimal number." A typical IP address looks like this:

70.42.251.42

The four numbers in an IP address are called octets because they can have values between 0 and 256 (2⁸ possibilities per octet).
Every machine on the Internet has its own IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP address that is assigned by the ISP when you dial in. That IP address is unique for your session and may be different the next time you dial in. In this way, an ISP only needs one IP address for each modem it supports, rather than for every customer.
If you are working on a Windows machine, you can view your current IP address with the command WINIPCFG.EXE (IPCONFIG.EXE for Windows 2000/XP). On a UNIX machine, type nslookup along with a machine name (such as "nslookup www.howstuffworks.com") to display the IP address of the machine (use the command hostname to learn the name of your machine).
For more information on IP addresses, see IANA.
As far as the Internet's machines are concerned, an IP address is all that you need to talk to a server. For example, you can type in your browser the URL http://70.42.251.42 and you will arrive at the machine that contains the Web server for HowStuffWorks. Domain names are strictly a human convenience.
If we had to remember the IP addresses of all of the Web sites we visit every day, we would all go nuts. Human beings just are not that good at remembering strings of numbers. We are good at remembering words, however, and that is where domain names come in. You probably have hundreds of domain names stored in your head. For example:

• www.howstuffworks.com - a typical name
• www.yahoo.com - the world's best-known name
• www.mit.edu - a popular EDU name
• encarta.msn.com - a Web server that does not start with www
• www.bbc.co.uk - a name using four parts rather than three
• ftp.microsoft.com - an FTP server rather than a Web server

The COM, EDU and UK portions of these domain names are called the top-level domain or first-level domain. There are several hundred top-level domain names, including COM, EDU, GOV, MIL, NET, ORG and INT, as well as unique two-letter combinations for every country.
Within every top-level domain there is a huge list of second-level domains. For example, in the COM first-level domain, you've got:

• howstuffworks
• yahoo
• msn
• microsoft
• plus millions of others...

Every name in the COM top-level domain must be unique, but there can be duplication across domains. For example, howstuffworks.com and howstuffworks.org are completely different machines.
In the case of bbc.co.uk, it is a third-level domain. Up to 127 levels are possible, although more than four is rare.
The left-most word, such as www or encarta, is the host name. It specifies the name of a specific machine (with a specific IP address) in a domain. A given domain can potentially contain millions of host names as long as they are all unique within that domain.

Because all of the names in a given domain need to be unique, there has to be a single entity that controls the list and makes sure no duplicates arise. For example, the COM domain cannot contain any duplicate names, and a company called Network Solutions is in charge of maintaining this list. When you register a domain name, it goes through one of several dozen registrars who work with Network Solutions to add names to the list. Network Solutions, in turn, keeps a central database known as the whois database that contains information about the owner and name servers for each domain. If you go to the whois form, you can find information about any domain currently in existence.
While it is important to have a central authority keeping track of the database of names in the COM (and other) top-level domain, you would not want to centralize the database of all of the information in the COM domain. For example, Microsoft has hundreds of thousands of IP addresses and host names. Microsoft wants to maintain its own domain name server for the microsoft.com domain. Similarly, Great Britain probably wants to administrate the uk top-level domain, and Australia probably wants to administrate the au domain, and so on. For this reason, the DNS system is a distributed database. Microsoft is completely responsible for dealing with the name server for microsoft.com -- it maintains the machines that implement its part of the DNS system, and Microsoft can change the database for its domain whenever it wants to because it owns its domain name servers.
Every domain has a domain name server somewhere that handles its requests, and there is a person maintaining the records in that DNS. This is one of the most amazing parts of the DNS system -- it is completely distributed throughout the world on millions of machines administered by millions of people, yet it behaves like a single, integrated database!
Name servers do two things all day long:

• They accept requests from programs to convert domain names into IP addresses.
• They accept requests from other name servers to convert domain names into IP addresses.

When a request comes in, the name server can do one of four things with it:

• It can answer the request with an IP address because it already knows the IP address for the domain.
• It can contact another name server and try to find the IP address for the name requested. It may have to do this multiple times.
• It can say, "I don't know the IP address for the domain you requested, but here's the IP address for a name server that knows more than I do."
• It can return an error message because the requested domain name is invalid or does not exist.

When you type a URL into your browser, the browser's first step is to convert the domain name and host name into an IP address so that the browser can go request a Web page from the machine at that IP address (see How Web Servers Work for details on the whole process). To do this conversion, the browser has a conversation with a name server.
When you set up your machine on the Internet, you (or the software that you installed to connect to your ISP) had to tell your machine what name server it should use for converting domain names to IP addresses. On some systems, the DNS is dynamically fed to the machine when you connect to the ISP, and on other machines it is hard-wired. If you are working on a Windows 95/98/ME machine, you can view your current name server with the command WINIPCFG.EXE (IPCONFIG for Windows 2000/XP). On a UNIX machine, type nslookup along with your machine name. Any program on your machine that needs to talk to a name server to resolve a domain name knows what name server to talk to because it can get the IP address of your machine's name server from the operating system.
The browser therefore contacts its name server and says, "I need for you to convert a domain name to an IP address for me." For example, if you type "www.howstuffworks.com" into your browser, the browser needs to convert that URL into an IP address. The browser will hand "www.howstuffworks.com" to its default name server and ask it to convert it.
The name server may already know the IP address for www.howstuffworks.com. That would be the case if another request to resolve www.howstuffworks.com came in recently (name servers cache IP addresses to speed things up). In that case, the name server can return the IP address immediately. Let's assume, however, that the name server has to start from scratch.
A name server would start its search for an IP address by contacting one of the root name servers. The root servers know the IP address for all of the name servers that handle the top-level domains. Your name server would ask the root for www.howstuffworks.com, and the root would say (assuming no caching), "I don't know the IP address for www.howstuffworks.com, but here's the IP address for the COM name server." Obviously, these root servers are vital to this whole process, so:

• There are many of them scattered all over the planet.
• Every name server has a list of all of the known root servers. It contacts the first root server in the list, and if that doesn't work it contacts the next one in the list, and so on.

Here is a typical list of root servers held by a typical name server:

; This file holds the information on root name servers
; needed to initialize cache of Internet domain name
; servers (e.g. reference this file in the
; "cache  .  " configuration file of BIND domain
: name servers).
;
; This file is made available by InterNIC registration
; services under anonymous FTP as
;     file             /domain/named.root
;     on server        FTP.RS.INTERNIC.NET
; -OR- under Gopher at RS.INTERNIC.NET
;     under menu     InterNIC Registration Services (NSI)
;        submenu     InterNIC Registration Archives
;     file           named.root
;
; last update:    Aug 22, 1997
; related version of root zone:   1997082200
;
;
; formerly NS.INTERNIC.NET
;
.                     3600000 IN  NS  A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET.   3600000     A   198.41.0.4
;
; formerly NS1.ISI.EDU
;
.                     3600000     NS  B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET.   3600000     A   128.9.0.107
;
; formerly C.PSI.NET
;
.                     3600000     NS  C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET.   3600000     A   192.33.4.12
;
; formerly TERP.UMD.EDU
;
.                     3600000     NS  D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET.   3600000     A   128.8.10.90
;
; formerly NS.NASA.GOV
;
.                     3600000     NS  E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET.   3600000     A   192.203.230.10
;
; formerly NS.ISC.ORG
;
.                     3600000     NS  F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET.   3600000     A   192.5.5.241
;
; formerly NS.NIC.DDN.MIL
;
.                     3600000     NS  G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET.   3600000     A   192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
;
.                     3600000     NS  H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET.   3600000     A   128.63.2.53
;
; formerly NIC.NORDU.NET
;
.                     3600000     NS  I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET.   3600000     A   192.36.148.17
;
; temporarily housed at NSI (InterNIC)
;
.                     3600000     NS  J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET.   3600000     A   198.41.0.10
;
; housed in LINX, operated by RIPE NCC
;
.                     3600000     NS  K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET.   3600000     A   193.0.14.129
;
; temporarily housed at ISI (IANA)
;
.                     3600000     NS  L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET.   3600000     A   198.32.64.12
;
; housed in Japan, operated by WIDE
;
.                     3600000     NS  M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET.   3600000     A   202.12.27.33
; End of File

The formatting is a little odd, but basically it shows you that the list contains the actual IP addresses of 13 different root servers.
The root server knows the IP addresses of the name servers handling the several hundred top-level domains. It returns to your name server the IP address for a name server for the COM domain. Your name server then sends a query to the COM name server asking it if it knows the IP address for www.howstuffworks.com. The name server for the COM domain knows the IP addresses for the name servers handling the HOWSTUFFWORKS.COM domain, so it returns those. Your name server then contacts the name server for HOWSTUFFWORKS.COM and asks if it knows the IP address for www.howstuffworks.com. It does, so it returns the IP address to your name server, which returns it to the browser, which can then contact the server for www.howstuffworks.com to get a Web page.
One of the keys to making this work is redundancy. There are multiple name servers at every level, so if one fails, there are others to handle the requests. There are, for example, three different machines running name servers for HOWSTUFFWORKS.COM requests. All three would have to fail for there to be a problem.
The other key is caching. Once a name server resolves a request, it caches all of the IP addresses it receives. Once it has made a request to a root server for any COM domain, it knows the IP address for a name server handling the COM domain, so it doesn't have to bug the root servers again for that information. Name servers can do this for every request, and this caching helps to keep things from bogging down.
Name servers do not cache forever, though. The caching has a component, called the Time To Live (TTL), that controls how long a server will cache a piece of information. When the server receives an IP address, it receives the TTL with it. The name server will cache the IP address for that period of time (ranging from minutes to days) and then discard it. The TTL allows changes in name servers to propagate. Not all name servers respect the TTL they receive, however. When HowStuffWorks moved its machines over to new servers, it took three weeks for the transition to propagate throughout the Web. We put a little tag that said "new server" in the upper left corner of the home page so people could tell whether they were seeing the new or the old server during the transition.
When someone wants to create a new domain, he or she has to do two things:

• Find a name server for the domain name to live on.
• Register the domain name.

Technically, there does not need to be a machine in the domain -- there just needs to be a name server that can handle the requests for the domain name. There are two ways to get a name server for a domain:

• You can create and administer it yourself.
• You can pay an ISP or hosting company to handle it for you.

Most larger companies have their own domain name servers. Most smaller companies pay someone. The history of HowStuffWorks is typical. When howstuffworks.com was first created, it began as a parked domain. This domain lived with a company called www.webhosting.com. Webhosting.com maintained the name server and also maintained a machine that created the single "under construction" page for the domain.
To create a domain, you fill out a form with a company that does domain name registration (examples: register.com, verio.com, networksolutions.com). They create an "under construction page," create an entry in their name server, and submit the form's data into the whois database. Twice a day, the COM, ORG, NET, etc. name servers get updates with the newest IP address information. At that point, a domain exists and people can go see the "under construction" page.
HowStuffWorks then started publishing content under the domain www.howstuffworks.com. We set up a hosting account with Tabnet (now part of Verio, Inc.), and Tabnet ran the DNS for HowStuffWorks as well as the machine that hosted the HowStuffWorks Web pages. This type of machine is called a virtual Web hosting machine and is capable of hosting multiple domains simultaneously. Five-hundred or so different domains all shared the same processor.
As HowStuffWorks became more popular, it outgrew the virtual hosting machine and needed its own server. At that point, we started maintaining our own machines dedicated to HowStuffWorks, and began administering our own DNS. We currently have four servers:

• AUTH-NS1.HOWSTUFFWORKS.COM 70.42.150.19
• AUTH-NS2.HOWSTUFFWORKS.COM 70.42.150.20
• AUTH-NS3.HOWSTUFFWORKS.COM 70.42.251.19
• AUTH-NS4.HOWSTUFFWORKS.COM 70.42.251.20

Our primary DNS is auth-ns1.howstuffworks.com. Any changes we make to it propagate automatically to the secondary, which is also maintained by our ISP.
All of these machines run name server software called BIND. BIND knows about all of the machines in our domain through a text file on the main server that looks like this:

@         NS    auth-ns1.howstuffworks.com.
        @         NS    auth-ns2.howstuffworks.com.
        @         MX 10 mail

        mail      A     209.170.137.42

        vip1      A     216.183.103.150
        www       CNAME vip1

Decoding this file from the top, you can see that:

• The first two lines point to the primary and secondary name servers.
• The next line is called the MX record. When you send e-mail to anyone at howstuffworks.com, the piece of software sending the e-mail contacts the name server to get the MX record so it knows where the SMTP server for HowStuffWorks is (see How E-mail Works for details). Many larger systems have multiple machines handling incoming e-mail, and therefore multiple MX records.
• The next line points to the machine that will handle a request to mail.howstuffworks.com.
• The next line points to the IP address that will handle a request to oak.howstuffworks.com.
• The next line points to the IP address that will handle a request to howstuffworks.com (no host name).

You can see from this file that there are several physical machines at separate IP addresses that make up the HowStuffWorks server infrastructure. There are aliases for hosts like mail and www. There can be aliases for anything. For example, there could be an entry in this file for scoobydoo.howstuffworks.com, and it could point to the physical machine called walnut. There could be an alias for yahoo.howstuffworks.com, and it could point to yahoo. There really is no limit to it. We could also create multiple name servers and segment our domain.
As you can see from this description, DNS is a rather amazing distributed database. It handles billions of requests for billions of names every day through a network of millions of name servers administered by millions of people. Every time you send an e-mail message or view a URL, you are making requests to multiple name servers scattered all over the globe. What's amazing is that the process is usually completely invisible and extremely reliable!

What began as a project helmed by Larry Page and Sergey Brin, two students in Stanford's Ph.D. program, is now one of the most influential companies on the World Wide Web: Google. At first, the students' goal was to make an efficient search engine that gave users relevant links in response to search requests. While that's still Google's core purpose today, the company now provides services ranging from e-mail to document storage. In less than a decade, Google evolved from a two-man enterprise to a multibillion-dollar corporation.

Torsten Silz/AFP/Getty Images Fair-goers use laptops at Google's stand at the Frankfurt Book Fair on Oct. 8, 2006. See more images of laptop computers.

How Many Zeroes?Google's name is a variation of the word "googol," which is a mathematical term for a one followed by 100 zeros. Page and Brin felt the name helped illustrate Google's monumental mission: Organizing billions of bytes of data found on the Web.

Today, Google's popularity continues to grow. In 2007, Google surpassed Microsoft as the most visited site on the Web [source: San Francisco Chronicle]. The company's influence on the Web is undeniable. Practically every webmaster wants his or her site listed high on Google's search engine results pages (SERPs), because it almost always translates into more traffic on the corresponding Web site. Google has also acquired other Internet companies, ranging from blogging services to the video-sharing site YouTube. For a while, Google's search technology even powered rival companies' search engines -- Yahoo relied on Google searches until developing its own search engine technologies in 2004 [source: cNet].
Google's influence isn't limited to just the Web. In 2007, Google executives announced their intention to enter the FCC's auction of the wireless spectrum in the 700 megahertz (MHz) band. That part of the wireless spectrum previously belonged to analog television broadcasters. Google entered the auction in order to foster competition within the wireless service industry. Google supported an open technology approach to wireless service in which consumers could use any device with any provider rather than face limited choices determined by the provider and its preferred vendors. In order to participate in the auction, Google had to prove it was ready to meet the reserve price for the spectrum: $4.6 billion.

What's the Word, Hummingbird?Google's interest in the 700 megahertz (MHz) spectrum helped fuel speculation that the company was looking to get into the cellular phone market. Rumors about a custom-designed Google Phone (the Gphone) spread across technology and gadget blogs across the Web. Andy Rubin, Google's director of Mobile Platforms, has yet to announce plans for a Gphone. However, he did reveal that Google was behind a mobile device software platform called Android. Android includes a smartphone operating system, user interface and applications.

In this article, we'll learn about the backbone of Google's business: its search engine. We'll also look at the other services Google offers to both average users and to commercial businesses. Then we'll take a quick peek at some of the tools Google has developed over the years. We'll also learn more about the equipment Google uses to keep its massive operation running. Finally, we'll take a closer look at Google the company.
In the next section, we'll explore the Google search engine.
Google's search engine is a powerful tool. Without search engines like Google, it would be practically impossible to find the information you need when you browse the Web. Like all search engines, Google uses a special algorithm to generate search results. While Google shares general facts about its algorithm, the specifics are a company secret. This helps Google remain competitive with other search engines on the Web and reduces the chance of someone finding out how to abuse the system.

Image courtesy GoogleGoogle's home page

Google uses automated programs called spiders or crawlers, just like most search engines. Also like other search engines, Google has a large index of keywords and where those words can be found. What sets Google apart is how it ranks search results, which in turn determines the order Google displays results on its search engine results page (SERP). Google uses a trademarked algorithm called PageRank, which assigns each Web page a relevancy score.

Does Whatever a Spider CanA search engine spider does the search engine's grunt work: It scans Web pages and create indexes of keywords. Once a spider has visited, scanned and categorized a page, it follows links from that page to other sites. The spider will continue to crawl from one site to the next, which means the search engine's index becomes more comprehensive and robust. To learn more about these programs, read How Search Engines Work.

A Web page's PageRank depends on a few factors:

• The frequency and location of keywords within the Web page: If the keyword only appears once within the body of a page, it will receive a low score for that keyword.
• How long the Web page has existed: People create new Web pages every day, and not all of them stick around for long. Google places more value on pages with an established history.
• The number of other Web pages that link to the page in question: Google looks at how many Web pages link to a particular site to determine its relevance.

Out of these three factors, the third is the most important. It's easier to understand it with an example. Let's look at a search for the terms "Planet Earth."



As more Web pages link to Discovery's Planet Earth page, the Discovery page's rank increases. When Discovery's page ranks higher than other pages, it shows up first on a Google search.
Because Google looks at links to a Web page as a vote, it's not easy to cheat the system. The best way to make sure your Web page is high up on Google's search results is to provide great content so that people will link back to your page. The more links your page gets, the higher its PageRank score will be. If you attract the attention of sites with a high PageRank score, your score will grow faster.

Hitting the LinksGoogle uses lots of tricks to prevent people from cheating the system to get higher placement on SERPs. For example, as a Web page adds links to more sites, its voting power decreases. A Web page with a high PageRank with lots of outgoing links can have less influence than a lower ranked page with only one or two outgoing links.

In the next section, we'll look at some of the specialized tools Google offers users.
As Google has grown, the company has added several new services for its users. Some of the services are designed to help make Web searches more efficient and relevant, while others seem to have little in common with search engines. With many of its services, Google has entered into direct competition with other companies.
Google's specialized searches are an extension of its normal search engine protocol. With specialized searches, you can narrow your search to specific resources. You can enter keywords into Google and search for:

• Images related to your keywords
• Maps
• News articles or footage
• Products or services you can purchase online
• Blog entries containing the keywords you've chosen
• Content in books
• Videos
• Scholarly papers

For these searches, Google has created specialized indexes that only contain relevant sources. For example, if you search for the terms "Planet Earth" in the news category, the results will include only news articles that contain those keywords. The results will look very different from Google's normal SERP.

Google on the GoYou can perform a Google search with any short message service (SMS) compatible cell phone, even if you can't access the Web with your phone. Simply text your query to 466453 (which spells GOOGLE on a phone pad). Google will send a response back within a couple of seconds.

In the last few years, Google has unveiled services that don't relate to search engines upon first glance. For example, Google's Gmail is a free Web-based e-mail program. When the service first launched, Google limited the number of users who could create accounts. The first group of users could invite a limited number of people to join the service, and so Gmail invitations became a commodity. Today, anyone can sign up for a free Gmail account.

Google's Gmail is now available to all users, but it was once a limited commodity.

Gmail organizes e-mails into conversations. This means that when you send an e-mail to someone and he or she replies, both e-mails are grouped together in a thread in your inbox. This makes it easier to follow the flow of an e-mail exchange. If you reply to your friend's response, Google will attach your message to the bottom of the thread. It's easy to navigate through the e-mail program and follow specific conversations.
Another free service from Google is Google Docs, a storage database and collaborative word processing program originally called Writely. Creating a Docs account is free and allows you to store up to 5,000 documents and images online. Each document can be up to 500 kilobytes, and each embedded image can be up to 2 megabytes. You can share documents on Google Docs, which allows your friends to view and make changes to documents. You can store all your documents on Google's servers and access them wherever there's an Internet connection.
In the next section, we'll look at some specialized Google tools.

Advanced SearchesWith an advanced search, you can use Google to retrieve the most relevant results for your keywords. You can search for documents written in a specific language or saved in a particular file format like .pdf or .rtf. You can tell Google where to look for the keywords, such as in page titles or headers. Google even allows you to limit searches to a single domain name. Each choice you make tells Google which index to use when returning your search results.

Google offers a popular tool called Google Maps, an online mapping service similar to MapQuest. Google uses map sources from companies like NAVTEQ and TeleAtlas, as well as satellite data from DigitalGlobe and MDA Federal, to create interactive maps. You can use Google maps to view an address' location or get driving directions to a particular destination.

Image courtesy Google Earth mapping service/NASA/TerraMetrics 2007 The Google Earth application

Google Maps has several view modes. The map view is a basic road map, satellite view overlays a road map on top of satellite photos of the region, terrain view creates a topographic map with a road map overlay, and the traffic view uses red, yellow and green to indicate congested major roadways in the area. Street view mode is available in select U.S. cities. Selecting street view in such locations as Orlando, Fla., gives you the option to view photos taken from street level. You can navigate through the city by clicking on arrows in the photographs, and you can rotate your view 360 degrees.

Smile, You're on Street View!Some people feel that Google's street view function is a violation of privacy. For example, homeowners who were behind in their yard work became worried that anyone viewing pictures of their home through Google would see a messy house, making it harder to sell the property in the future.

Google Maps can also integrate business information. You can use Google Maps like a search engine to find a business, such as "HowStuffWorks, Atlanta, GA," which will show you our office's location. You can also search for general businesses. If you're in the mood to eat sushi in San Francisco, you can type "sushi, San Francisco," and with a click of the Search button, Google Maps will display a map of the city with several sushi restaurants tagged.
A related product to Google Maps is Google Earth, an interactive digital globe. It uses the same satellite images licensed for Google Maps, but you must download the application and install it on your computer. Google Earth requires an Internet connection to be fully functional, though you can still view locations on the globe even if you aren't connected. To learn more about this program, read "How Google Earth Works."
The Google Toolbar is another handy tool available for Firefox or Internet Explorer users. The toolbar has customizable buttons. Each button maps to a particular function, which can include anything from viewing a Web site's PageRank to translating a word from one language to another.

The Google Desktop application

Google Desktop is another free application you can download. This program lets you search your computer the way you would search the Internet using the Google search engine. You can also choose to download Google Gadgets, computer programs that integrate seamlessly into your desktop. Each gadget does something different. Gadgets include clocks, calendars, news feeds and weather reports.
In the next section, we'll look at some of the ways Google generates revenue.
Unlike some Internet companies, Google has multiple ways of generating revenue beyond private investment or selling shares of stocks. Google uses three ways to partner with merchants and advertisers: Google Checkout, Google AdWords and Google AdSense.

Stand Honda/AFP/Getty Images In 2004, Google became a publicly traded company on NASDAQ.

Google Checkout is a service designed to make online purchases easier for both the consumer and the retailer. On the consumer end, users create a free Google Checkout account. Part of the account creation process includes entering a credit or debit card number, which Google stores in a secure database. When the user visits a retailer that subscribes to Google Checkout, he or she can click on the checkout option and Google facilitates the transaction. This means that the user doesn't have to enter a card number every time he or she makes a purchase.
Retailers can set up Google Checkout accounts for free, but as of February 2008, Google charges a 2 percent plus 20-cent fee per transaction. For example, if a customer buys a $10 item from a merchant, Google will charge that merchant 40 cents for that transaction.
Another way Google generates revenue is through a pair of Web advertising services called AdWords and AdSense. With AdWords, advertisers can submit ads to Google that include a list of keywords relating to the product, service or business. When a Google user searches the Web using one or more of those keywords, the ad appears on the SERP in a sidebar. The advertiser pays Google every time a user clicks on the ad.

Google's AcquisitionsGoogle isn't just famous for creating and providing useful services -- it's also bought a few innovative companies and integrated them. These include YouTube (a video-sharing Web site), Blogger (a web log service), Picasa (a photo-sharing service) and Jaiku (an SMS and micro-blog service).

AdSense is similar, except that instead of displaying ads on a Google SERP, a webmaster can choose to integrate ads into his or her own site. Google's spiders crawl the site and analyze the content. Then, Google selects ads that contain keywords relevant to the webmaster's site. The webmaster can customize the location and color of the sidebar containing the ads. Every time someone clicks on an ad on the webmaster's site, the webmaster receives a portion of the ad revenue (Google gets the rest).

Google Adsense ads appear on HowStuffWorks' pages.

With both AdWords and AdSense, Google's strategy is to provide targeted advertising to users. Google believes that by providing advertising relevant to the information the user is already searching for, the chances of someone following the ad are greatly increased [source: Google].
In the next section, we'll learn about the equipment Google uses to provide users with these tools and services.
Back in 1998, Google's equipment was relatively modest. Co-founders Larry Page and Sergey Brin used Stanford equipment and donated machines to run Google's search engine duties. The equipment at that time included:

• Two 300 megahertz (MHz) Dual Pentium II servers with 512 megabytes (MB) of memory
• A four-processor F50 IBM RS6000 computer with 512 MB of memory
• A dual-processor Sun Ultra II computer with 256 MB of memory
• Several hard drives (some of which were housed in a box covered in LEGO bricks) ranging from four to nine gigabytes (GB) for a total of more than 350 GB of storage space [source: Google Stanford Hardware]

Today, Google uses thousands of servers to provide services to its users. Google's strategy is to use relatively inexpensive machines running on a customized operating system based on Linux. A program called Google File System manages the data on Google's servers [source: Google Cluster Architecture].

You Got ServedHow many servers does Google have? The company is quiet about the subject, but estimates range from 200,000 to more than 450,000 machines.

Google uses servers for different tasks. Google's Web servers receive and process user queries, sending the request on to the next appropriate server. Index servers store Google's indexes and search results. Google uses document servers to store search summaries, user information, gmail and Google Docs files. Ad servers store the
advertisements Google displays on search pages. Google divides the information on each index server into 64 MB blocks. There are three copies of each block of data, and each copy is stored on a different server running on a separate power strip. The blocks of data are distributed semi-randomly so that no two servers have the exact same collection of data blocks. That way, if there's a problem with one server, the data will still exist in other machines. Using multiple copies of data to prevent an interruption in service is called redundancy.
A master computer manages each set of servers. The master computer's job is to keep track of which servers hold each block of data in the event of a catastrophe. If one server goes down, the master computer redirects all traffic to the other servers containing the same data.

Google and BandwidthSome webmasters feel that Google's spiders consume too much bandwidth per month. When a spider follows a link to a Web page, it uses up bandwidth. Most Web hosting services charge webmasters for bandwidth consumption. If the webmaster feels that Google's spiders are a liability, he or she can create a robot.txt file in the root directory of the Web page that will tell the spiders to ignore the site.

In the next section, we'll learn more about Google's corporate culture.
Google has come a long way since Sergey Brin and Larry Page networked a few computers together at Stanford. What started as a modest project is now a multibillion-dollar global organization that employs more than 10,500 people around the world. Brin and Page are still very much involved with Google's operations -- they are Presidents of Google's Technology and Products divisions, respectively.
In early January 2008, Google's market capitalization figure (Google's stock price multiplied by the number of outstanding company shares) was more than $200 billion. Google's stock is listed in NASDAQ as GOOG, and at the beginning of 2008 Google had more than 312 million outstanding shares in the marketplace [source: Google].

David Paul Morris/Getty Images The Googleplex -- Google's headquarters in Mountain View, Calif.

Google's headquarters are in Mountain View, Calif. Google cheekily calls its campus the Googleplex -- a combination of the words "Google" and "complex" and a play on the term googolplex: One followed by a googol of zeroes. Life at the Googleplex is pretty sweet. Here's just a small list of the amenities you can find there:

• Several café stations where employees can gather to eat free food and have conversations
• Snack rooms stocked with goodies ranging from candy to healthy foods like carrots and yogurt
• Exercise rooms
• Game rooms with video games, Foosball, pool tables and pingpong
• A baby grand piano for those who enjoy tickling the ivories

In addition to these amenities, Google employees receive a comprehensive benefits package that includes not only medical and dental coverage, but also a host of other services. These include tuition reimbursement, a child care center, adoption assistance services, an on-site doctor, financial planning classes and lots of opportunities to gather with coworkers at special corporate events. Google's philosophy also places importance on nonprofit work, and so Google will match up to $3,000 of any employee's contributions to nonprofit organizations.
Google has asserted itself as one of the most dominant forces on the Internet. Still, the company says its mission is "to organize the world's information and make it universally accessible and useful" [source: Google]. With a goal that lofty, it's a good bet that the people behind Google feel their work is just beginning.

Green GoogleBesides being an Internet juggernaut, Google is also a leader in pursuing environmentally friendly methods of conducting business. Google launched an eco-friendly initiative they call Renewable Energy is Cheaper than Coal (RE< />). Google plans to switch to renewable energy sources including solar, geothermal and wind power. Google also plans to make significant investments in renewable energy companies.

When Dale Dougherty of O'Reilly Media coined the term "Web 2.0," he probably didn't know he was stirring up a hornets' nest. He was trying to come up with a catchy name for an Internet conference focused on the most effective ways to use the Web. The term caught on, and some people began to use it beyond its original purpose. Ever since the phrase "Web 2.0" gained traction, people have debated its definition. More than a few Internet experts question whether Web 2.0 even has a meaning at all.

Marshall Brain's personal Web page belongs in the Web 1.0 category, but his blog has more Web 2.0 features. But what does this mean, exactly? See more images of Web pages.

Tim O'Reilly, founder and CEO of O'Reilly Media, took a stab at defining Web 2.0 more than a year after the first Web 2.0 Conference. He posted an explanation on his blog that spanned five pages of text and used a lot of marketing terms and jargon. Some people might find O'Reilly's explanation more confusing than helpful, but his main point was that Web 2.0 refers to people making connections with other people through the Web, as they do on these Web sites:

• Social networking sites, like MySpace or Facebook
• Blogs and micro-blogs, like LiveJournal or Twitter
• Sites that allow users to contribute content, like wikis
• Sites that let users share content, like YouTube

But defining Web 2.0 was only half of the problem. The other half had to do with the use of "2.0." The number suggested that this was a new version of the World Wide Web. If Web 2.0 was real, what was Web 1.0? Were there still Web pages on the Internet that fell into the Web 1.0 classification? If you search the Web, you'll find no shortage of answers to these questions. Unfortunately, there's no agreement on the answers.
We can understand what Web 1.0 is only if we assume that there's a Web 2.0. In this article, we'll use O'Reilly's definition of Web 2.0 to figure out what Web 1.0 means. In the next section, we'll look at the definitive explanation for Web 1.0.
It's hard to define Web 1.0 for several reasons. First, Web 2.0 doesn't refer to a specific advance in Web technology. Instead, Web 2.0 refers to a set of techniques for Web page design and execution. Second, some of these techniques have been around since the World Wide Web first launched, so it's impossible to separate Web 1.0 and Web 2.0 in a time line. The definition of Web 1.0 completely depends upon the definition of Web 2.0.

Ironically, the Web page for the 2007 Web 2.0 summit works more like a Web 1.0 page.

With that in mind, if Web 2.0 is a collection of approaches that are the most effective on the World Wide Web, then Web 1.0 includes everything else. As for what it means to be "effective," Tim O'Reilly says that it's providing users with an engaging experience so that they'll want to return to the Web page in the future. Here's a collection of strategies O'Reilly considers to be part of the Web 1.0 philosophy:

• Web 1.0 sites are static. They contain information that might be useful, but there's no reason for a visitor to return to the site later. An example might be a personal Web page that gives information about the site's owner, but never changes. A Web 2.0 version might be a blog or MySpace account that owners can frequently update.
  
  
• Web 1.0 sites aren't interactive. Visitors can only visit these sites; they can't impact or contribute to the sites. Most organizations have profile pages that visitors can look at but not impact or alter, whereas a wiki allows anyone to visit and make changes.
  
  
• Web 1.0 applications are proprietary. Under the Web 1.0 philosophy, companies develop software applications that users can download, but they can't see how the application works or change it. A Web 2.0 application is an open source program, which means the source code for the program is freely available. Users can see how the application works and make modifications or even build new applications based on earlier programs. For example, Netscape Navigator was a proprietary Web browser of the Web 1.0 era. Firefox follows the Web 2.0 philosophy and provides developers with all the tools they need to create new Firefox applications.

Tiny Bubbles in the WebTim O'Reilly says that by looking at the Web sites that were around before and after the so-called dot-com bubble burst, people can see which Web strategies work best. By 2000, the Web had been around for several years and many investors were pouring money into small, unproven Web companies. Many of these companies had no proven means of generating revenue, and eventually the wave of speculative investments crashed. O'Reilly argues that the Web companies that survived the crash did so because their approach was better suited to the Web. In his Web 2.0 explanation, he says that the companies that are now thriving after the dot-com crash learned valuable lessons from the Web 1.0 companies that are no longer around.

Is it always a bad idea to take a Web 1.0 approach in Web design? Find out on the next page.
If Web 2.0 is a collection of the most effective ways to create and use Web pages, is there any reason to make a page that follows the Web 1.0 model? It may sound surprising, but the answer is actually yes. There are times when a Web 1.0 approach is appropriate.

The Amazon Web site was quick to embrace Web 2.0 concepts in features like its customer book reviews.

Part of the Web 2.0 philosophy is creating a Web page that visitors can impact or change. For example, the Amazon Web site allows visitors to post product reviews. Future visitors will have a chance to read these reviews, which might influence their decision to buy the product. The ability to contribute information is helpful. But in some cases, the webmaster wouldn't want users to be able to impact the Web page. A restaurant might have a Web page that shows the current menu. While the menu might evolve over time, the webmaster wouldn't want visitors to be able to make changes. The menu's purpose is to let people know what the restaurant serves; it's not the right place for commentary or reviews.
Another example of a good Web 1.0 approach is information resources. Wikipedia is an online encyclopedia resource that allows visitors to make changes to most articles. Ideally, with enough people contributing to Wikipedia entries, the most accurate and relevant information about every subject will eventually be part of each article. Unfortunately, because anyone can change entries, it's possible for someone to post false or misleading information. People can purposefully or unwittingly damage an article's credibility by adding inaccurate facts. While moderators do patrol the pages for these acts of vandalism, there's no guarantee that the information on an entry will be accurate on any given day.

World Book Encyclopedia's Web page is an example
of a Web 1.0 information resource.

On the flip side of the coin are official encyclopedias. Encyclopedia entries are fact-checked, edited and attributed to a specific author or entity. The process of creating an encyclopedia article is very structured. Perhaps most importantly, there is a stress on objectivity. The author of an encyclopedia entry must present facts without being subjective; a person making an edit to a Wikipedia article could have a personal agenda and as a result hide certain facts or publish false information. While Wikipedia can be a good starting place to find information about most subjects, it's almost always a bad idea to use it as your sole source of information.
The boundary between what counts as Web 1.0 and Web 2.0 isn't always clear. Some Web sites are very static but include a section for visitor comments. The site as a whole might follow the Web 1.0 approach, but the comments section is a Web 2.0 technique. Even Web experts disagree on how to classify Web pages, and some think that it's a mistake to even try labeling them at all.
There's no denying that some Web strategies are more effective than others. In the end, whether or not there's such a thing as Web 1.0 is a moot point. The important thing is to learn how to use the Web to its full potential.