I prefer privacy and I really think it is not delusional but optional! I share way more here than in real life. I think a lot of people "can't handle the truth". No their own truth, and most certainly not someone else's truth. I don't blame them.
Depending on your job it can also get you sacked (I am sure there are notable exceptions as Angela described).
Probably the only one I can have meta-communication with is my sister. We can be radically honest with each other, and I would not mind her finding me here.