The WHOIS information of a domain name is a collection of a variety of details which are publicly accessed via special lookup websites or a command line. The protocol which makes this possible bears the same name and you could easily see the firm through which a domain address 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 specific domain name. All this info has to be correct and up-to-date at all times; if not the domain registration may be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), therefore you should always ensure that the WHOIS details of your domains are accurate. Updating the WHOIS for a number of country-code TLDs is limited, so whenever you register a new domain, you should double-check the info that you are submitting.