A domain name registration company, sometimes called an ICANN (Internet Corporation for Assigned Names and Numbers) host, is a web site that offers registration services for a fee. In exchange for this service, the owner of the domain name must provide an IP address, usually of their own, as well as a host name and a valid email address. If they fail to do so, they will not be able to register the domain name. Registration is often required for non-profit organizations, government-related sites, and sites that contain adult content.