You're attempting to extend property rights such that they provide privacy. I don't think that works, except in cases of Intellectual Property, wherein the idea itself has monetary value and can therefore be "stolen" simply by being seen. But the only way to legally protect your IP is to disclose it via the patent office, so still no.
I own a car. Yes, I am about to make a car-Facebook analogy. I am very
If you look at my car, you haven't violated my property rights. If you write down my license plate, you haven't violated my property rights. If, from my bumper stickers and whatnot, you determine that I have a kid named Billy who plays football, a daughter named, Billy, who plays cello, that one of my kids is an honor-roll student (Billy, most likely), that I have a wife, that I most likely voted for Ralph Nader in 2004, and from the make and model of the car ascertain with reasonable certainty which socio-economic bracket I fit, you still
have not violated any of my Constitutional Rights. Would it be creepy? Yes. The same is true of gathering info on Facebook, message boards, etc.