The WHOIS information of an domain is a collection of numerous details that are publicly accessed through specific lookup sites or a command line. The protocol which makes this possible bears the same name and you can very easily see the firm through which an Internet domain has been registered, the creation, expiration and last update dates as well as the names, postal and email address of the individuals listed as Registrant (owner), Administrative, Technical and Billing contacts for a particular Internet domain. All this info must be legitimate and up-to-date all the time; if not the domain name registration could be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), this means you should always make sure that the WHOIS details of your domains are legitimate. Updating the WHOIS for several country-code TLDs is limited, so when you register a completely new domain, you should double-check the info you are submitting.