Even if you did export your data, you can't export your friends to a competing social network. The real reason there's no threat to Facebook is because of the network effect.
One could even argue that Facebook is destroying their network effect by not allowing people to see all posts. The fact that Linkedin, Meetup, Twitter, heck even the new myspace all exist, there are lots of networks with varying degrees of network effects which could slowly take facebook share until the tipping point is crossed.
I’m not predicting facebook’s demise, rather I’m stating that network effects are important, but have not been proven to create a long term sustainable competitive advantage.
Feeling a little pretentious today? Your point was valid, but your tone was off-putting.
I think we can all agree that the network effect exists, its only its power and longevity are what is really in question.
The network effect kicks in at a certain critical point. If you created a really compelling social network and added the feature s.t. people could say, "import from facebook", choosing your facebook login/pw, then if enough people did this, critical mass would be reached. The network effect just states that this critical mass might take awhile to reach, but it's not impossible. Facebook disallowing you from exporting your data makes it so competing networks cannot reach that critical point quickly enough.