Your friends' applications are sucking your data!

Sounds like a long-winded B-grade horror movie title, doesn't it? Your friends' applications are sucking your data! But these third-party applications are very likely siphoning personal info from your profile, if you haven't adjusted privacy settings.

Confused? It's like this: each time your friends add an application, your info could be shared with developers whose applications you haven't even installed! This even extends to things like the type of relationship you're looking for, religious views, even your Wall!

Granted, not all these are on by default. But it shows how much Facebook developers can (and I hate this term but I'm going to use it) drill down to minute detail. Think of what marketers can do with this data!

To find out what info you're sharing, go to the Application Privacy page (under Privacy), and look at What Other Users Can See via the Facebook Platform. You can see a list of things that you can or can't share:

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• Share my name, networks, and list of friends, as well as the following information:

• Profile Picture
• Basic Info
• Personal info (activities, interests, etc.)
• Current location (i.e. town, city etc)
• Education history
• Employment history
• Profile status
• Wall
• Notes
• Groups I belong to

• Events I'm invited to
• My Photos
• Photos of me
• Relationship status
• Online presence
• What type of relationship I'm looking for
• Which gender I'm interested in
• Who I'm in a relationship with
• Religious views

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Tick or untick as appropriate. As you can see, you have no choice but to share your name, network and list of friends.

If you want absolutely nothing shared, then underneath this box, you may see "Do not share any information about me through the Facebook API". But very likely, if you've added any applications, this will be grayed out. Click on "Why can't I see this?" and you'll see this explanation:

You are unable to fully opt out of sharing information through Facebook Platform because you are currently using applications built on Platform. To enable this option, you need to remove any applications you have added, and remove your permissions to all external applications that you may have used.

Basically, this means you'll need to uninstall all the applications in order to turn off all sharing.