This page covers databases for searching registered and pending patents and trademarks, registered copyrights, and domain names.
Information about the owner of a domain name is in the Whois data from the Registrar of that domain name. The Whois information is generally limited to contact information, if it is available at all. There is no single database for searching all the registered domain names. You can find some information at the following databases, by going to the Registrar's website and checking its Whois database, or searching through commercial vendors (such as Thomson).
