This might be a cliche answer but why not make a simple list of the pros and cons of keeping Facebook, it'll make the decision a little more easier to see possibly.
If you do end up keeping Facebook, that's fine, just don't post anything on it but use it strickly for communication with your friends. And about the privacy thing....we all better get used to the fact that we are being spyed on in one form or another and there's nothing we can do about it unfortunately. The only thing to do about that is just be aware that we have no privacy anymore and maybe to block it out so we don't think about it. Ok, enough of my rant
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When u hit the walls of sanity, u have no-where to go....