The extension reportedly prevents data being sent back to Facebook across the one million sites that already use the Facebook Connect service. "Facebook is notified whenever you visit one of the more than one million sites on the web that use Facebook Connect and has a history of leaking personally identifiable information to third parties," the description of the extension explains. "Turn off the flow of your data to them! Facebook Disconnect blocks all traffic from third-party sites to Facebook servers, yet you’ll still be able to access Facebook itself."
Kennish claims he created the extension instead of deleting his Facebook account and was not asked to do so by either Google or Facebook. Of course, he's employed by Google, which is trying very hard to compete with Facebook, but denies it. We believe he wasn't ordered to create the extension, but somehow we doubt his current employer is annoyed with his initiative.