WHOIS is a protocol which makes it possible to see the info a specific domain name has been registered with through a command line or through the use of special web-based lookup sites. This info includes the names, address and email address of the owner, admin, technical and billing persons as well as the registrar company the domain name has been purchased through, the creation and expiration dates. Aside from some country-code TLDs that have certain limitations, the WHOIS details of any Internet domain can be modified freely whenever you want, which is quite vital given that in accordance with the policies of the top-level Internet Corporation, ICANN, all details have to be current and valid all of the time. Inability to conform with these policies may result in losing the ownership of a domain and in some cases a domain may even be removed from the Domain Name System and released for free registration.