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September 27, 2017

What's the difference between .com, .net and others?

'Infrequently Asked Questions' seeks the answer

While most of us spend our time on ".com" websites, the alphabet soup of web addresses continues, .net, etc.

But what are they all for? 

Curious, we reached out to Gaurav Naik, assistant research professor at Drexel University's College of Computing and Informatics, for an answer. 

For starters, what are these names for?

  • The world is full of questions we all want answers to, but are either too embarrassed, time-crunched or intimidated to actually ask. With Infrequently Asked Questions, we set out to answer those shared curiosities. Have a question you want answered? Send an email to, and we’ll find an expert who can give you the answer you’re craving.

In the operation of the internet, a domain name (e.g. is translated to a numerical Internet Protocol (IP) address that is used for locating and identifying the service or device for that particular domain. A domain name consists of multiple parts that are separated by dots. We call the right-most part the top-level domain (TLD) and the left-most parts are called subdomains of the domain name. For example, in “," “edu” is the TLD, “drexel” is a subdomain of “edu” and “www” is a subdomain of “” 

What's the origin story of these domains, and what are the fundamental differences between them? 

The first set of standards for domains, developed in the 1980s, defined an initial set of generic top-level domains (or gTLDs) such as .arpa, .com, .gov, .edu, .net, .int, .mil, .org; and two-letter country codes for top-level domains (e.g. .us, .uk). The standards originally designated “.com” for commercial purposes, “.gov” for government, “.mil” for military, “.edu” for education, “.net” for internet networks, “.int” for intergovernmental organizations and “.org” for any other organizations. 

On a technical level, there is no difference between these domains and, in fact, the .com, .net, and .org domains offer open registration, so anyone can register those domains. Because it was one of the first generic top-level domains, .com is the world’s most popular, and most recognizable domain by users in the United States.  

Does anyone regulate or oversee this domain system? 

From the 1980s until 2000, the domain system was operated by the Information Sciences Institute (ISI) under contract from the U.S. government. As the internet grew globally, the U.S. government initiated a policy to transfer operation of the domain system to the private sector to allow for global participation in internet management. In response to this policy, a newly created nonprofit organization, called Internet Corporation of Assigned Names and Numbers (ICANN), was awarded a contract to execute the technical work of maintaining and coordinating the domain system and other internet identifier functions on a global basis. 

From 2000 until 2016, ICANN operated this function under the oversight of the U.S. government. On Oct. 1, 2016, the U.S. government allowed the contract with ICANN to expire, thus passing the stewardship of the domain system to ICANN’s global, multi-stakeholder community. 

".ly" has been showing up more and more. What's with that? Are there more like that on the way? 

This is an example of a domain hack—.ly is actually the country code domain that was established for the country of Libya in the ’90s. But today, you’re seeing country codes used to create domains that are also concatenated versions of brand names. For example, Apple uses (.es is the country code of Spain) and Google uses (.gl is the country code for Greenland). There are many other examples of domain hacks in use today and their usage will continue to grow. 

Is anyone still using ".net"? 

Absolutely—while .net was originally intended for internet related domains, it is still one of the more popular generic top-level domains. For example, both AT&T and Comcast use their .net domains for their residential e-mail service, so subscribers for either service would get a or e-mail address. 

Can anyone register as .mil, .gov or .edu? 

Today, both .mil and .gov are still controlled by the U.S. government. Their usage is restricted to government (for .gov) and military purposes (for .mil). The .edu domain is available to only U.S.-based postsecondary institutions and organizations that are institutionally accredited. 

Will we ever run out of domain names? I can't imagine how many .com names have been taken by now. 

Domain names are not free–there are annual registration fees to be paid. While many .com domain names have been taken, they aren’t gone forever. People drop domains all time by not electing to renew their domain registration. Those domains become available to others to register after a short period of time. 

In addition, there is a healthy market for domain names. There are many domain name investors who are holding names for the right buyer and there are others who willing to sell their domain name to other companies for the right price. 

Now, eventually, we’ll run out of useful and usable .com domain names, so ICANN has been developing a program to introduce new, generic, top-level domains to the global internet. 

How do you see the domain-name concept evolving in the next few years?

Through the 2000s, the expansion of domains was limited to the addition of .aero, .biz, .name, .info, and .mobi, among several others. However, in 2012, ICANN began accepting applications for a more dramatic expansion. ICANN received 1,930 applications, and as of Aug. 31, 2017, 1,227 new top-level domains have been introduced to the global internet. 

Examples of popular new top-level domains include .top, and .loan.  

Anything to add that people might find useful or interesting? 

If you have an interest in how the internet evolves and want to have a say, it is free to participate in ICANN’s meetings and processes.