Facebook leaks IP addresses. Facebook reckon data portability is criminal, making it very clear that they own your data, not you. Facebook forced people to use "connections", anyone who didn't was unlinked. Facebook threatens to sue a developer for collecting the data they have collected, because they know that data's worth.
Hell, even Wired thinks that Facebook’s Gone Rogue - and it’s Time for an Open Alternative. Sure, this might seem like a strange set of links from someone who just installed the "like" button on adland, I just don't expect the mass exit from Facebook quite yet. Mainly because people are lazy. Facebook has shut down sites like seppukoo and Suicide 2.0 as they made it too dang easy to leave facebook.
Now you'll have to do it the hard way, and this means Facebook still stores you data somewhere, even if you plan on never coming back. Deleting all your images, interests and friend connections before leaving takes time. And what if you want to keep that carefully honed list of favorite movies? There's the aptly named give me my data app that'll grab all that for you, and save it on your own computer.
Quick use it before Facebook sends a cease and desist to them as well! But of course, the reason people don't leave FB is because people don't leave FB (this is why they make it so hard, guys).
Remember Sixdegrees? I do, I was on it. It's the pre-facebook FB, and if you had friends on it who wanted you to join, it would pester you with emails, much like Facebook does today. I joined, connected to friends, decided it was a waste of my time after a few goes and set up an access rule in my sendmail so that sixdegrees.com could never email me. I didn't even notice when the site died. (I have a similar access rule for facebook, as people keep asking me to join that too, unaware that I deleted my account more than 5 years ago because I didn't want to be on facebook and poked by the socially awkward dweeb who sat behind in biology class in eight grade, jesus christ people, we loose touch for a reason.) But think about it, you're on FB, and at least one (and that is by a very conservative estimate) of your friends is a rabid friends collector who believes that FB is a game where the object is to collect as many friends as possible.
This connects you to so many people you may or may not know, or care much about. Remember the Creative Director of DraftFCB was arrested on suspicion of attempted murder, because one of his friends happened to be a gal he went to a class in UNI with, and it was her ex-husband that was almost killed. What if someone you're "friends" with on FB is a complete nutcase, and decides one day to crash a plane into the IRS building. God forbid you gave him a "like" on any random status update just hours prior, you'll be hauled in for a quick chat with the cops for sure.
Don't forget that everyone else can see your stuff, like that depressed woman had her sick-leave benefits withdrawn because she looked happy on Facebook and countless other stories. Use of social networking sites in investigations isn't new, but I'm sure there are a lot of far-off aquaintances to Faisal Shahzad who wish they never accepted his friend request right now.
Oh, don't even get me started on the fact that once you're newsworthy all your facebook photos are fair game for every news outlet, keep that in mind next time you upload your party images as they might be used as your identifying image if you die in some horrible bombing. You don't look that good with a lampshade on your head. Facebook can do anything they want with your pictures, including selling/giving them to the AP. The age of privacy is over. Oh really? I am not where you think I am, my Flickr account is deliberately tiny. My twitter updates may clue you in to what a warped sense of humor I have and what my music tastes are, but you don't know everything about me, nor who I consider to be my friends. I like it that way.