What are some social networking sites similar to LinkedIn?

shelstar27 asked:


My uncle has to get a new job, and it was recommended that he join some social networking sites such as LinkedIn to gain connections and speak to others in his profession. I was asked to gather a list of these sites for him, but the only thing I can think of is LinkedIn. I know there are ones like Facebook and MySpace, but I mean more professional-geared sites. Any suggestions?

Social Networking Sites