From the activeness of http://MoreAlly.com, I think gamers on Google+ is growing.
Facebook does it big, but Google+ does it better. Google+ does gaming with actual GAMERS in mind. Here's why I'm using G+ for social games and NOT Facebook. Check it out.

http://thenextweb.com/socialmedia/2011/09/27/why-im-using-google-for-social-games-and-not-facebook/
Shared publiclyView activity