Synecdochic writes Why Monetizing Social Media Through Advertising Is Doomed To Failure and I tend to largely agree with her. (Her write-up is very layperson friendly for those not in e-commerce or social media.)
The only point I disagree on is that I’m not sure the Web 2.0 bubble will burst. I think it will start to topple and then someone will figure it out. The downfall will stop if Companies get a clue. Or perhaps 95 of them.