The social media landscape is changing faster than that of prehistoric earth. New sites pop up all the time, the balance of power shifts rapidly from one service to another, and people constantly jump from one social bandwagon trend to the next.
I like the breakdown of the social world into 7 categories with Google and Facebook being at the center. Games gets it’s own category and so do services for comments and community interaction under ‘Discuss’. Check it out and click through for a bigger version!