[TheOtherHobbes]

There's always a Facebook-shaped niche. It used to a CompuServe-shaped niche. Then it turned into an AOL-shaped niche.

But it's the same niche, for more-or-less the same user profile.

And it'a a very vulnerable niche. FB may seem unstoppable at the moment, but it really isn't.

The number of ways it could be replaced is non-trivial.

Zuckerberg knows this, hence internet.org, which is really just a way to promote lock-in in the developing world. But that's a lot less useful than it seems if FB loses traction in the developed world.