I believe we just getting into a period of social networks phenomena, where everyone is sick and tired of the big Facebook, and soon a fresh new thing will pop-up... This network will be smoother, nicer and smarter approach to social networks than Facebook is and will serve same users, just more mature. Sure few years ago FB was such giant that noone could touch it. But since then the cost of Cloud-computing and serving millions of connections per hour went drastically down, and its never been a rocket science to design and program basic social network.

I just wonder if we already have such network and I just happened not to hear about it yet :)