One that has worked for me - if they have a personal website, check the domain registry using a service such as http://whois.com http://whois.com, and if not a

One that has worked for me - if they have a personal website, check the domain registry using a service such as http://whois.com http://whois.com, and if not a private registration, you will see the registrant's email :) Prime example http://www.whois.com/whois/500hats.com http://www.whois.com/whois/500hats.com