One of the things that many people don't realize about Facebook is that applications and quizzes that your friends run have access to your profile information. We created a Facebook quiz that demonstrates exactly how much information it can pull from friends' profiles.

In order to share as little information as possible with applications that your friends run on Facebook, follow these steps.

• Click on the Account menu option in the top right corner of the screen.
• Select Privacy Settings from the dropdown menu.

• Click on Applications and Websites on the page that appears.

• Click the Edit Settings button to the right of the What your friends can share about you text.

• Deselect all of the checkboxes on the What Your Friends Can Share About You page and click on the Save Changes button.
  

There you go. That's as safe as you can make yourself from applications run by your friends. Unfortunately, they can still access your name, your profile picture, and your connections, but there's currently no way to protect this data on Facebook. You can sign our petition asking Facebook to give users more control of their privacy here.