Facebook knows it could lead to some major backlash too, so they're being very conservative with the initial rollout. If you go to Yelp, it's actually hard to tell at first glance that any data sharing has occurred. Go to Pandora and it will know what bands you like, but who is going to get upset about that? And Docs.com doesn't appear to be open to the public yet.
As the program expands, though, there could be a pretty serious shitstorm. I don't think people understand what the 'Everyone' option means, and this could be the first time they realize what they signed up for during Facebook's privacy overhaul last December, when Everyone became the default.