WHOIS is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information. The protocol stores and delivers database content in a human-readable format. The WHOIS protocol is documented in RFC 3912
Domain privacy (often called Whois privacy) is a service offered by a number of domain name registrars. A user buys privacy from the company, who in turn replaces the user’s information in the WHOIS with the information of a forwarding service.