The WHOIS info of an domain is a collection of numerous details which are openly accessed using special lookup websites or a command line. The protocol which makes this possible has the same name and you can very easily see the organization where an Internet domain has been registered, the creation, expiration and last update dates as well as the names, postal and e-mail address of the people listed as Registrant (owner), Administrative, Technical and Billing contacts for a specific domain name. This info has to be correct and up-to-date constantly; if it's not the domain address registration may be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), therefore you should always make sure that the WHOIS details of your domains are legitimate. Updating the WHOIS for a variety of country-code TLDs is limited, so when you register a completely new Internet domain, make sure you double-check the info that you're submitting.