Google CPC works because it ties in buyer behaviour with advertisers. The solution to driving revenue from pageviews must either connect up existing behaviour with advertisers (where can I buy an X), or create a compelling new behaviour. For example, in the early days of newspapers, it wouldn't have been obvious to look in the back for classified ads, but buyers learnt this and now know to look in the back for the ads.
The power in social networks is the group of trusted friends. I'm sure some sort of group question along the lines of 'do you guys think I should buy an LCD or Plasma TV' with voting, or something similar, would develop new behaviours, particularly amongst consumers of products they aren't completely familiar with (anything from cars to financial products). Once you develop this behaviour in a social network, selling ads into it is a cinch.
The power in social networks is the group of trusted friends. I'm sure some sort of group question along the lines of 'do you guys think I should buy an LCD or Plasma TV' with voting, or something similar, would develop new behaviours, particularly amongst consumers of products they aren't completely familiar with (anything from cars to financial products). Once you develop this behaviour in a social network, selling ads into it is a cinch.