The DNS (Domain Name System) is the largest digital database in the world, which holds the domain name information of every site in the world. This database is split up over thousands of individual web servers known as “Name Servers” or “DNS Servers” that maintain the integrity and continuity of the internet.
The DNS database can be searched by anyone through the WhoIS DNS lookup services, however it is possible to register a domain name privately so that registration information is not made available to the public. Without the domain name system the internet would not exist as we know it today. When you register a domain name you are actually adding new information to this already unfathomably large database.