Myths about privacy on Facebook
Myth One: Facebook owns whatever I post and can sell it to third parties
While it's true that whatever you post online will forever exist somewhere in the far reaches of the Internet, but Facebook doesn't own your content. However their user agreement does grant Facebook non-exclusive, royalty-free licensing rights to content you post like photos and videos. Unfortunately we can't modify the user agreement, but you can change your privacy and app settings to fit your preferences.
Myth Two: Third-party apps can see most my Facebook activity like my photos, status updates, comments, etc.
If you use Facebook Connect (i.e. signing into another app with your Facebook login info), these third-party apps can only view information that you have made public. Just like with Myth One, you can control what you share publicly by adjusting your privacy settings. BUT, there are bits of info that a third-party app is entitled to no matter how you set your privacy. Name, profile, picture, gender, networks, user ID and list of friends. This is why sometimes an app can tell you "Five of your friends have used our app already." If an app wants more info from you, it will prompt you to allow it. You have complete control in this sense.
With these non-myths in mind, there's no real need to fear potential privacy issues on Facebook. By simply adjusting your settings and controlling which apps you allow to access your content, you can remain in complete control.
Source: Social Media Today