As I see many of my Facebook friends in a flurry of excitement to join Google + and invite everyone they know, a problem emerges. Facebook reached a tipping point where critical mass was achieved, and people had one place that we could find (almost) all of our online friends, or easily send a message to someone we hadn’t talked to in a long time. If half the people on my Facebook friend list left and moved to another social network, I don’t think I would have the incentive to follow and manage multiple social networks. But I also believe most of those people feel as I do… the gathering of accessible people is more important than the features of the gathering place.
Once you reach a critical mass, only fracturing can occur. Everyone in that mass does not move as one to another service or purpose. This will pose serious problems to any competition, and likely explains why a more viable competitor to Facebook has yet to emerge. Much like taking on the current largest MMO, World of Warcraft, you need more than marketing money and a strong IP to sway people away from a critical mass.
I’m really interested in how people are going to respond to new services like Google +. I predict any competitor to Facebook will gain a lot of attention for a short time, but ultimately will not gather enough people to reach a new critical mass. Those services will then be forced to either die off or specialize, turning into a community focused on a smaller range of user needs.