I agree with Dave Winer:
Senator Lindsey Graham asked Zuck the right question on Tuesday. Who are your competitors? The answer is they have none, though Zuck wouldn’t say that. That is the big problem. Solve it and all the others go away.
Zuck tried to laugh off the question, but the answer was as clear as day and he knew it. In the social-networking business, Facebook is the monopoly to end all monopolies.