Last night, I noticed that a whole bunch of my Facebook friends posted a "Privacy Notice" to their walls, or stuccoed it to their timelines, or whatever it is you do on Facebook now. The notice reads in part that "any governmental structure" does "NOT have...permission to utilize...profile information nor any of the content contained herein" and that they are "strictly prohibited from disclosing, copying, distributing, disseminating, or taking any other action against me with regard to this profile and the contents herein." According to the privacy notice, for some reason now that Facebook is a publicly owned company, posting the privacy notice means that the government can't hold anything you post on your Facebook wall against you in court. This is of course bullshit. It's along the lines of that dumb "are you a cop?" urban legend.
As Gizmodo explains, when you signed up for Facebook, you agreed to their privacy guidelines, and those privacy guidelines are total shit. If you care that much about your privacy, you shouldn't be using Facebook. And you definitely should not EVER be posting illegal acts—photos of drug use, mentions of trespassing, that sort of thing—on your Facebook wall. No cut-and-paste job is going to protect you in court. Facebook is public, and you should assume that everything you do on Facebook is public and that everyone—friends, family, law enforcement agencies—can see it. Full stop. The end.