Domain name usually refers to the name of a website. The domain name system controls everything related to a domain name. Each website has a specific IP address. But it is difficult to remember the website with IP. So for the convenience of remembering, the domain name is used instead of the IP address. The first commercial domain name , TLD .com, was first commercially used on March 15, 1985 by Cambridge-based computer firm Symbolics.com on their website Symbolics.com . In December 2009, they registered 190 million domain names.