XeeMe has a list of all social networks in the world.

http://xeeme.com/_/System/AppsPub/SMDir/index.cfm

Centillien is one of the 40 global social networks and the only dedicated for companies.

    Centillien

    Centillien

    Social network for companies. Full public profile, advertising, blogs, videos, events, groups. We have the most functional social network in the world