Facebook Beacon

this is pretty cool... Facebook Beacon is a way for you to bring actions you take online into Facebook. Beacon works by allowing affiliate websites to send stories about actions you take to Facebook...

If you are logged in to Facebook and visit a Beacon Affiliate, an action you take (like writing a review, watching a vid or purchasing an item), may trigger that website to want to publish a story to Facebook. you can accept or reject whether that information is published on your page.