Signing up for a Facebook account, or any free online service, comes with an implicit bargain: Use it as much as you want—check your News Feed, like a status, poke a friend—and in return, the company will collect your data, and use it to serve you ads both on Facebook and around the web. But what appears to be a simple exchange has become anything but. This is not a screed about deleting your Facebook account—although if you want to, here's how.

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