The original post was "The question is: "does a reasonable, prudent person (an average person) feel that what they do/post/share on Facebook is private?"
I voted yes. If you assume most people are somewhat prudent then they are just delusional. Certainly there can't be that many idiots out there, or are there? I guess it is how you define prudent and reasonable.... Now people like me are a bit more than prudent, (and some would say unreasonable), and have never had a Facebook account. I don't trust any of them. As Raindog pointed out nothing you tell 200 people is private. There are two different issues there. On Facebook you just get slammed twice, by Facebook, and by your own stupidity.
Just like this or any other forum, what you post is out there for all to see. What is generally missing on forums
such as this is the data mining, data manipulation and sophistication and of course the ubiquitousness of Facebook, and people on this forum don't usually brag about whose wife they bonked, what store they robbed, etc.