Top Level Domains

As you may have noticed, every domain name, website name, and e-mail address ends with a dot followed by two or more letters. This final bit is an indicator of the top-level domain. Learn more about the top-level domain choices now as you read on.

Domains From the Top Down

Every website that you visit has a Uniform Resource Locator (URL)—the string that you type into the location bar or address bar at the top of your browser window in order to access the site. The URL includes a variety of information, including the registered domain name that is specific to the site, and always ends with the top-level domain (TLD) which is the first level of division on the Internet, grouping websites into categories. The same TLD will end any e-mail address associated with the website as well.

There are three distinct types of TLDs:

• Country code TLDs (cTLDs) are domain names that specify countries or dependent territories, usually matching the ISO 3166 codes for the countries, with a few exceptions.

• Generic TLDs (gTLDs) are domain names that represent classes or categories of organizations. This is the type that is usually under consideration when a person sets up a business or personal website.

• Infrastructure TLDs (iTLDs) are for the Internet infrastructure, as you might imagine. The only functional one currently is .arpa, which stands for "Address and Routing Parameter Area" and is not something that someone buying or selling domain names or setting up a business or personal website has to be concerned about.

TLDs are managed by the Internet Corporation for Assigned Names and Numbers, popularly known as the ICANN. Control of each TLD is delegated by the ICANN to a domain name registry.

Choices and More Choices

The top-level domains available today include some that date back to 1985 when the first set were created, and others that are new. For practical purposes, it is more useful to categorize them by this article has all rights reserved and is copyright by 100 Best whether they are restricted (which may mean that they are sponsored) or unrestricted (which usually means unsponsored). Further, sponsored TLDs (sometimes referred to as sTLDs) operate under a sponsor that represents the particular community for which the TLD is or particular interest, while unsponsored TLDs operate under the aegis of the ICANN acting on behalf of the global Internet community.

gTLD	Specified Use, If Restricted	Sponsored?	Restricted?
.aero	Air transport industry	yes	yes
.asia	Companies, individuals, and organizations in the Asia/Pacific region	yes	yes
.biz	Businesses using the Internet for commerce	no	yes
.cat	Catalan culture and language	yes	yes
.com		no	no
.coop	Cooperatives	yes	yes
.edu	Post-secondary educational institutions	no	yes
.gov	US Federal, state, and local government	no	yes
.info		no	no
.int	International organizations established by treaty	no	yes
.jobs	Employment-related sites	yes	yes
.mil	US military and the Department of Defense	no	yes
.mobi	Sites delivering content to mobile devices	yes	yes
.museum	Museums	yes	yes
.name	Limited to one's own personal name (legal or customary or pseudonym) and fictional characters that one holds trademark or service mark for.	no	no
.net		no	no
.org		no	no
.pro	Legal, medical, and accountancy professionals and organizations	no	yes
.tel	Internet-communication services	yes	yes
.travel	Travel industry	yes	yes

The TLD .xxx has been rejected by ICANN, and .post—designed for postal agencies—is still under consideration.