Michael Wolff on Facebook
The growth of its user base and its ever-expanding page views means an almost infinite inventory to sell. But the expanding supply, together with an equivocal demand, means ever-lowering costs. The math is sickeningly inevitable. Absent an earth-shaking idea, Facebook will look forward to slowing or declining growth in a tapped-out market, and ever-falling ad rates, both on the Web and (especially) in mobile. Facebook isn’t Google; it’s Yahoo or AOL.
Also see Doc Searls: After Facebook Fails:
But totally personalized advertising is icky and oxymoronic. And, after half a decade or more at the business of making maximally-personalized ads, the main result is what Michael calls “the desultory ticky-tacky kind that litters the right side of people’s Facebook profiles.”