Searching for just the right social network niche? You don't have to search any further than SocialNetworkList. Their directory has over 700 social networking sites listed that you can search through. Unlike some of the other engines, SocialNetworkList only lists social networking sites, nothing else.
New social networks are being created each day. SocialNetworkList seems to be doing a pretty good job keeping up with them all. Help them out. If you know of a social network they don't have listed, submit it to them, then everyone else will be able to find it too.