On a similar vein, I was talking with a friend a few days ago and we were remarking that the newest plugged in generation (my kids and his kids) has absolutely NO interest in Facebook, so if you've got some stock, sell it quick. Maybe FB will figure it out and realize they need a complete rethink if they want to get this new generation, but I'm not optimistic.
I use it obviously to stay in touch with friends across the ocean, but I mostly lurk and 'like' anyway.
Google+ seems to be struggling to catch on - it seems only about 10-15 people I know are on it, so I check it once a month maybe.