It would be interesting to see demographics of FB users. I would bet recent trends shift toward more older users and fewer younger users. If their user base is shifting that way, then it's over for the 18-24 age group, but the boomers will create new behavior/usage models that FB would be well to exploit. That age group has more money and is about to have more leisure time as they retire. Advertisers couldn't wire money to FB accounts fast enough to target that market. Think BoomerBook.