Do you take some of those quizzes you see your friends post on Facebook? Which Harry Potter Character are you? Who is your soulmate? What is the most often word you use?
Most of them require you to grant them access to your Facebook profile so they can pull some information off them, or so that you can post the result of the quiz to Facebook once it's done.
Did you know that once you are done taking the quiz, those sites continue to have access to your profile and/or timeline information?
They may be a fun distraction, and appear harmless, but these sites now have basic access to your Facebook profile, that you granted them. This level of access can be used to collect stats about your, your interests, who your friends are, and much much more. As they are not part of Facebook's company, they can do what they wish with this information once collected. Including sell that information to other companies or other organizations.
A lot of this information is used to target you with ads. If you do this often, it is not much different than making your entire Facebook Profile public for the world to see. And if the purpose of the site is to attempt to scam you, you could lose much more.
Sample Access Screen
See related article in Parenting Bytes. On Komondo.com. And on BetaNews.com
To revoke this access after you are done, is actually very easy to do. Within your Facebook profile settings is a page that lists all the 3rd party sites and apps you've granted access. To see them, go here: https://www.facebook.com/settings?tab=applications
There will be a little X next to each one you can use to remove them, click on that, and a message box will appear to confirm that you want to revoke access.
If you remove one by accident, then next time you visit that website it will ask you once more to grant access. There may be some sites you are comfortable using your Facebook profile to log into.
Revoking access may not have prevented the site from collecting information about you in the first place however.
As always, please be wary on Facebook and other social media sites. Once your account is created, you've agreed to the terms and conditions and the only way to get out of that is to delete the account permanently.