The unique name that identifies an Internet site. The Internet is made up of hundreds of thousands of computers and networks, all with their own domain name or unique address. Domain names always have two or more parts separated by dots. A given server may have more than one domain name, but a given domain name points to only one server.

For example, "whitehouse.gov" is the domain name belonging to the Whitehouse computer system. Once a system administrator registers a unique domain name, subaddresses can be assigned to the machines and people on the local network. So the President's e-mail address is "president@whitehouse.gov," the Vice-President's is "vice-president@whitehouse.gov," and so on. Each corresponds to a unique IP address. The machine that serves up the Whitehouse web pages is called www.whitehouse.gov.

Domain names typically consist of some form of the organization's name and a suffix that describes the type of organization. For example, IBM has registered the domain name "ibm.com"; Xerox corporation has registered "xerox.com." Registration is on a first come, first served basis. The domain name suffix is assigned based on the type of organization. The main suffixes are:

.com - business or commercial site
.edu - educational institutions
.org - non-profit organizations
.mil - military organization
.net - network provider
.gov - government institution

In addition, sites can have an extension that indicates the country where the domain is located. For example:

.au - Australia
.ca - Canada
.dk - Denmark
.ge - Germany
.uk - United Kingdom
.us - United States

The main domain names are assigned and indexed by the InterNIC project (a joint project of the National Science Foundation, AT&T, and Network Solutions, Inc.). Each of these addresses is actually an alias of a numerical address (called an IP address). The IP number for the Whitehouse for example, is 198.137.240.100. To access the Whitehouse Internet site, you could use the IP number if you like, but most people prefer to use the quasi-English domain name alias "whitehouse.gov."

The first step toward getting yourself one of those "yournamehere.com" addresses is to find a name that isn't taken. Once you find a free name (there are plenty of companies out there that would love to help you in your search), then you have to register it with Internic, the organization that keeps track of which domain names correspond with what IP numbers (there's a US$70 registration fee). And that's not all. You have to keep on paying on an annual basis to keep that domain name yours (a $35 maintenance fee). All in all, it can be a fairly substantial investment in time and money. But if you plan on having your own little corner on the Web for years to come, then stake a claim now, because those names are going like hot cakes.