Whois - is a program used to interrogate a public database that provides information regarding who owns domain names. This program has become less useful as many domains are now 'locked' to prevent spammers from acquiring email addresses. Whois records store the identity of the owner of each domain online, except for those that hide such information. Indeed, some domain registrars allow the ownership information to remain hidden, a feature often taken advantage of by large scale spammers.