As of today, there is a new privacy setting called “Instant Personalization” that shares data with non-Facebook websites and it is automatically set to “Allow”.
According to Facebook:
“You’ll find a personal and social experience the moment you arrive on our select partner sites — Docs.com, Pandora, and Yelp. We’re working closely with these partners so you can quickly connect with your friends and see relevant content on their sites. These sites personalize your experience using your public Facebook information. When you arrive on these sites, you’ll see a notification from Facebook at the top of the page.
You can easily opt-out of experiencing this on these sites by “No Thanks” on the blue Facebook notification on the top of partner sites.”
To disable this feature, go to Account > Privacy Settings > Applications and Websites > Instant Personalization and uncheck “Allow”.
(Thanks Arun Pattnaik)