Is there some sort of metric out there that quantifies the number or percentage of people that care enough about privacy to drop out of Facebook in disgust? Wha

Is there some sort of metric out there that quantifies the number or percentage of people that care enough about privacy to drop out of Facebook in disgust? What if FB is right and most people don't care about comprehensive privacy features? It may simply be enough for FB to keep random stalkers and identity thieves away. It's easy to imagine that the Ebay effect will stick to FB and it'll be the only heavyweight social network site around for some time.