Unless you're a Luddite, you're bound to know of ".com," the Internet's most common address suffix.
You've also probably heard of ".gov," for government sites, and ".edu," for educational institutions.
Did you know Antarctica has its own suffix, too? It's ".aq."
The aviation industry has ".aero" and porn sites have ".xxx." There's ".asia" for the continent, plus suffixes for individual countries such as Thailand (".th") and South Korea (".kr"). Thailand and Korea also have addresses in Thai and Korean.
There are currently 310 domain name suffixes -- the ".com" part of Web and email addresses. Now, the organization that oversees the system is poised to accept hundreds or thousands more. Possibilities include ".invest" and ".Canon."
In the early days of the Internet, each computer network simply had its own name. A hierarchical naming structure called the Domain Name System was created in the mid-1980s as the Internet grew. With such a system, Columbia University could have "Columbia.edu" and Columbia Sportsware Co. could have "Columbia.com." The Columbia Foundation could have "Columbia.org."
The system began with scores of country-specific domains and a handful of generic ones, including ".com," ".gov" and ".mil." International organizations got ".int" a few years later, in 1988.
That was largely the system in place until 2000. That was when the Internet Corporation for Assigned Names and Numbers, formed just two years earlier to oversee the address system, approved the creation of seven names, including ".info," ".aero" and ".museum." ICANN opened bidding again in 2004; seven have been added to the system from that round, including ".xxx."
Meanwhile, ICANN approved ".ps" for the Palestinian territories (in 2000) and ".eu" for the European Union (in 2005). That's because those two were on a country-code list kept by the International Organization for Standards, which in turn takes information from the United Nations. More recently, ICANN approved country names in languages other than English -- so India has ones for Hindi, Urdu and five others.
An expansion plan before ICANN on Monday would streamline procedures for creating names and allow for an endless number.
Just as names get added, names can disappear. Yugoslavia's ".yu" is gone, as is East Germany's ".dd." There's no longer an ".um" for the U.S. "minor outlying islands," which include the Midway Islands. Websites there can use ".us." Following East Timor's independence, ".tl" transitioning from ".tp."
Others simply go unused. Great Britain has ".gb" but websites there use ".uk." Likewise, ".sj" for the Arctic territories of Svalbard and Jan Mayen is uninhabited; their Norwegian administrators want residents to use Norway's ".no" domain.
Some legacies simply won't go away. ICANN has faced resistance in its efforts to get rid of the Soviet Union's ".su."