Forgive me if I'm wrong because this might be something different, but didn't Facebook have this whole Beacon fiasco a year ago? It resulted on a user's ability to opt out of using Beacon, as well as a public apology from Zuckerburg himself.

http://www.readwriteweb.com/archives...on_apology.php

Or was that just surrounding the news feed on facebook posting where you'd been recently/what you'd bought.