Block Sites from Using Your Facebook Login with Adblock PlusFacebook's new Instant Personalization Program allows other sites to access your Facebook data and connect you with people on those sites. Not only can you turn this feature off, but you can keep sites from retrieving your Facebook information with Adblock filters.
Not only does Facebook have an agreement with sites like Yelp and Pandora, but we've already seen that Facebook bugs can cause other, non-compliant sites to add applications to your profile, as long as you're logged into Facebook while you browse. Reader Saudrapsmann shows us how to keep this from happening in the future:
These four separate filters for AdBlock+ made it so not even the Facebook Privacy Scanner could see that I was logged into Facebook:Just go into Adblock Plus' preferences, click add filter, and copy and paste each of the above as a separate filter. Now, even if you're logged into Facebook, outside sites will not be able to tell, so your accounts won't automatically link with one another.
You should also turn off Facebook's Instant Personalization Program in your Facebook privacy settings. Note that doing this without adding the filters doesn't block you from future bugs in the system, and if your Facebook has already connected to a site, you'll have to go into your Facebook settings and delete the added application. You'll also have to go to your Yelp, Pandora, or Microsoft Docs.com account and delete the friends that Facebook added for you.
(Copied and pasted from: http://lifehacker.com/5542041/block-sites-from-using-your-facebook-login-with-adblock-plus )