Facebook has a privacy issue that will start to annoy people, it has already.
People do not care about privacy.
Yes, the privacy issue is very disturbing to IT industry people, media people, lawyers, soapbox Senators, etc.. But not average folks.
It's our own fault, (myself and anyone else who has an FB account that contains personal info).
Matt Cutts aside, do you know anyone who left FB in protest?
I went as far as starting a FACEBOOK DATA SHARING should be "OPT IN" not "OPT OUT" group -- it's attracted 104 people... On the other hand, the group "PULL YOU PANTS UP YOU LOOK LIKE A friggin IDIOT" has 1,014,792
The mentality is "keep it light, have fun", so in regards to data being sold, shared, whatever --- people are ambivalent -- they want FB, they don't really want their data mis-used, but as long as they don't think about it, it doesn't bother them -- there is no "nagging resentment", no groundswell of users ready to leave.
I still stand by my prediction -- native FB search is gonna kill off a bunch of GOOG search traffic -- and if they get really good at it, people may have little reason to leave the site for anything, (like AOL users who didn't know there was an "internet" outside of AOL).