The WHOIS information of a domain name is a collection of many details that are publicly accessed using special lookup sites or a command line. The protocol which makes this possible has the same name and you could effortlessly see the organization through which a domain name has been registered, the creation, expiration and last update dates along with the names, postal and e-mail address of the people listed as Registrant (owner), Administrative, Technical and Billing contacts for a particular domain address. This info must be legitimate and up-to-date constantly; otherwise the domain address registration can be challenged. The latter is a policy of ICANN (the Internet Corporation for Assigned Names and Numbers), therefore you must always make sure that the WHOIS details of your domain names are valid. Updating the WHOIS for numerous country-code TLDs is limited, so any time you register a brand new domain, make sure you double-check the info that you're submitting.