I installed this a while back
Works great.
Wherever there is a facebook button, it overlays a little gate icon to show it has detected (and blocked) the slurper.
Never had a farcebook account and never will. Ergo, they should not be able to track me around the web and this nice little tool does precisely that.
(I have also disabled flash 'cookies' without going to the website and asking for it - it is really simple).
Biting the hand that feeds IT
