Hmmm... it would be good to know how all these compare - I'm running disconnect: http://www.disconnectere.com/ and ghostery. Now someone is suggesting WidgetBlock. To me Ghostery seems to block more than disconnect - but I don't know how they work "under the hood". It seems silly to run 3 or 4 separate plugins for the same purpose!
Right, and Ghostery detects and blocks FB connect, as well as Google Analytics, AdSense and many other services. Very useful extension. Could be more intuitive though, it took me a few minutes to get the blocking right.
I'm a fan of WidgetBlock, a chrome extension that simply blocks all major offsite social networking widgets, whether its facebook like buttons, tweet this buttons, the facebook connect thing, etc.
It's stated reason for doing this is to improve page load times, which it certainly does, but it does just as well to protect your privacy.
I'm all for a transparency and control, but this has to be more effortless--a side-effect of something users would be happy to do anyway--especially for the average user if it is to be successful. I believe a social media aggregator can position themselves to do this. Facebook knows certain things about me, Twitter others, Google others, etc. What I surf online isn't always indicative of my true interests.