I was just taking a look at my facebook privacy settings. I was actually trying to fix a bug that won't let me upload photos from my iPhone 4, but I stumbled across a group of settings that I was rather annoyed at. So I'm sharing them here in case anyone else wants to turn these off. You may all know about this one already, but I didn't, so I'm sharing.
Here was the screen I eventually found that was troubling:
Based on what it says here, I'm going to assume that if one of my facebook friends grants access to an application, game, or website, then that application will also have access to everything I have checked here that I also share with my facebook friends. The screen you see above is what was checked by default; I have never modified these settings. Personally, I choose to opt out of the "more social experience."
Anyway, if you want to find this screen, too, here's how you find it. In the top right hand corner of your facebook page, click on Account > Privacy Settings.
You will see this screen:
Click on Edit your settings from the Apps and Websites section. On the next screen, click on Edit Settings next to Info accessible through your friends.
You will then see the screen from before:
Select or deselect whichever options you're comfortable with. Hope this helps.