I think if there's any challenger to Facebook as the dominant social network, it could well be WhatsApp. They're gathering a very large network of teenage user

I think if there's any challenger to Facebook as the dominant social network, it could well be WhatsApp. They're gathering a very large network of teenage users, completely avoiding the web, and becoming an alternative to both Twitter and email for group messaging. When you look at what they provide, it's pretty much everything I use from Facebook, without the noise.