[hansef]

The whole argument here is predicated on the idea that Facebook won't figure out ways to provide more value to and derive more value from its userbase, and that advertisers won't figure out how to adapt to social advertising as a medium more effectively. Big brand marketing is very much in a radio-to-television-style transition right now: just because the old bag of tricks doesn't work when glued onto a new channel doesn't mean that social will never provide value to media buyers. Facebook WANTS their advertisers to succeed, and you can bet there are a lot of very smart people thinking about this problem right now.

I think the far bigger threat to Facebook is in the "it stops being cool" market fragmentation possibility. As long as a huge percentage of people in the world are spending a chunk of their time on Facbook, I wouldn't bet against eventually finding a way to market to them effectively.