Adam sez, "MoveOn.org launched a campaign pressuring Facebook to stop violating people's privacy by revealing what they bought online.
A new Facebook feature called Beacon automatically shares books, movies, or gifts that Facebook users buy on web sites across the Internet. Without authorization, Facebook shares these information with a person's Facebook 'friends' which can number in the hundreds or thousands. MoveOn's campaign includes an online petition addressed to Facebook, a protest group within Facebook, and paid ads on Facebook."
Link to Facebook group, Link to MoveOn campaign
(Thanks, Adam!)