The WHOIS info of a domain name is a collection of a number of details which are freely accessed using special lookup Internet sites or a command line. The protocol which makes this possible has the same name and you could easily see the organization through which a domain name 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 domain name. This info must be valid and up-to-date constantly; otherwise the domain 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 accurate. Updating the WHOIS for numerous country-code TLDs is limited, so when you register a completely new domain address, you ought to double-check the info you're submitting.