Yesterday brought yet more proof that putting all your personal eggs into a social network basket may not be such a hot idea, especially if you (or your friends) stumble into the crosshairs of law enforcement.

The Electronic Frontier Foundation released documents it acquired via a Freedom of Information Act request about . Among them: a Department of Justice presentation on how to use Facebook, MySpace, Twitter, LinkedIn, and so on to gather intel on suspects and witnesses, friendly or otherwise.

(My theory: They finally heard about on Facebook and decided to take a closer look.)

The document -- using false identities to befriend suspects and learn more about them -- which violates the terms of service for most of these networks. (You never lie on your Facebook profile, do you?)

The arguments given for going undercover: "communicate with suspects/targets; gain access to nonpublic info; map social relationships/networks."