The biggest privacy issue here are the social plugins. They're easily embedded in existing sites using an iframe which is hosted by facebook.
As more sites adopt these, Facebook will be able to track every site you visit on the web. I don't know about you, but I'm not comfortable letting Facebook know which sites I visit.
Google adsense/doubleclick is fairly prevalent and has the same issue. You can opt out of it with Google though: http://www.google.com/privacypolicy.html -- the Facebook settings I have seen aren't clear about their data retention policies and what 'opting out' really means.
As more sites adopt these, Facebook will be able to track every site you visit on the web. I don't know about you, but I'm not comfortable letting Facebook know which sites I visit.
Google adsense/doubleclick is fairly prevalent and has the same issue. You can opt out of it with Google though: http://www.google.com/privacypolicy.html -- the Facebook settings I have seen aren't clear about their data retention policies and what 'opting out' really means.