.com, .net, .org and other website suffixes are known as “top-level domains” (TLDs). While we normally see only a few of these, there are hundreds of them – and there may be thousands more soon.
Top-level domains are managed by the Internet Assigned Numbers Authority (IANA), which is run by the Internet Corporation for Assigned Names and Numbers (ICANN).
Generic Top-Level Domains
Perhaps the most common top-level domains are .com, .net, and .org. Originally, each had a unique purpose:
- .com: Commercial (for-profit) websites
- .net: Network-related domains
- .org: Non-profit organizations
However, these top-level domains all offer open registration – anyone can register a .com, .net, or .org domain for a website (for a fee). The distinction between the domains has largely been lost, although there are still non-profit organizations that prefer .org.
There are a variety of other domains that were added later to take some off the stress off of the original generic top-level domains (gTLDs), including .biz and .info. However, fewer websites use these top-level domains – there’s more brand recognition associated with a .com domain. Currently, .com is by far the most popular top-level domain – nearly 50 percent of the websites Google visits use the .com top-level domain. (Source)
Open vs. Closed TLDs
In contrast to the above top-level domains, which are “open” in that they allow anyone to register a domain without meeting any qualifications, many TLDs are “closed.” For example, if you want to register a .museum, .aero, or .travel domain, you must verify that you’re a legitimate museum, air-travel, or tourism-related entity.
Country-Specific Top-Level Domains
There are hundreds of country-specific top-level domains. For example, the .uk domain is for the United Kingdom, the .ca domain is for Canada, and the .fr domain is for France.
Some of these country-specific domains are closed and only allow citizens and businesses in the country to register, while some allow open registration for everyone to register.
For example, the popular .ly domain, notably used by bit.ly and other URL-shortening services, is actually the country-specific domain for Libya. It allows largely open registration, although there are some restrictions around the type of content a website with a .ly TLD can contain.
Uniquely, the USA has some country-specific domains that aren’t country codes:
- .edu: Educational institutions in the US
- .gov: US government entities
- .mil: US military use
Future Top-Level Domains
In 2012, ICANN allowed corporations to apply for new generic top-level domains. The list of applications is long – For example, Google applied for domains such as .google, .lol, .youtube, and .docs. Many companies applied for domains matching their company name, such as .mcdonalds and .apple. A variety of companies also made a land grab for generic domain names such as .pizza, .security, .download, and .beer.
None of these new domains has come online yet, but it seems like we’ll be seeing a lot more top-level domains soon.
For a complete list of the current top-level domains in use, check out the root zone database page on the IANA’s website.