I think the point is that you could sign up with LocalTimes' funky new daily deals site using Facebook Connect one day, clicking through a generic permissions screen as you do, because you trust LocalTimes aren't going to do anything spammy. If you know what the signup permissions mean (which if you're an average person, you don't) you decide you can live with some of your friends wondering whether you bought the half price pedicure you perused.

A month later, you're Googling for a local STI clinic and have no reason to believe that clicking on the top result (LocalTimes' eclassified section) is going to share your interest in local STI clinics with all your social network. But it is, because LocalTimes' single signon site which you're already logged into makes no distinction about what is and isn't to be shared, but they have made efforts to adopt this revolutionary new form of passive sharing which is going to push up their pageviews.