The Internet is a collection of various computer networks located all over the world. While the computers address each other by numeric codes, that would make the use of the Internet very hard for humans. That is where domains come in.

Each network has a domain name. For example, Phone Cowboy’s domain name is “PhoneCowboy.com”. The domain name system was originally designed to allow each network to name every one of its computers. For example, our web server might be name “www.phonecowboy.com”, our ftp server might be named “ftp.phonecowboy.com”, etc.

The “com” in our domain name is called the “top-level domain”, or, simply, TLD.

There are several three-letter TLDs, of which the most common are “com”, “org”, and “net”. Note that the dot is not a part of the TLD, rather it separates the name of the network from the TLD the same way a dot separates the name of the computer from the name of the network.

Originally, the TLD told you something about the nature of the network: A “com” network was commercial, an “org” belonged to a non-profit organization, a “net” domain name was reserved for Internet Service Providers.

While in theory this is still true, in reality it is no longer the case. Generally, most people—individuals or businesses—try to get the “com” domain first, and only if it is already taken do they try one of the other two.

Alas, many people do not know the difference and automatically assume that every domain name ends with “dot com”. That is why it is better to go with the “com” TLD even if your site is not commercial: You have better chances people will remember your domain name.

There are other three-letter TLDs but their use is still reserved to specific types of networks: “edu” for educational institutions, “mil” for the military, “gov” for various governmental branches.

Secondly, there are two-letter TLDs which are supposed to tell us what country a network is located. For example, if a domain name ends in “.us”" it is in the USA. Further, with the “us” TLD you can even tell which state the network is. For example, a domain name ending with “.wi.us” is in Winsconsin, etc.

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