The WHOIS information of a domain name is a collection of many details that are openly accessed using special lookup websites or a command line. The protocol which makes this possible carries the same name and you could easily see the organization where an Internet domain has been registered, the creation, expiration and last update dates together with the names, postal and e-mail address of those listed as Registrant (owner), Administrative, Technical and Billing contacts for a particular domain address. This information should 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 ensure that the WHOIS details of your domain names are valid. Updating the WHOIS for a number of country-code TLDs is limited, so when you register a brand new domain name, you should double-check the info that you're submitting.