[untamedmedley]

My guess is the lack of adequate revenues that lead to real profits. Last I read, Facebook was breaking even. As they grow toward a billion users, I imagine those costs will rise. This is fine if ad revenues can keep up, but last I checked their average CTR was less than half a percent.

Facebook is odd in that it improves on a previous solution (communication tools: mail, phone, cellphones), but doesn't charge for the utility it brings.