Have you considered the authenticity of what gets posted? Some post only those things about themselves that they want to share. Some only post when they are not busy doing, so that what you get reflected in the technological mirror is just their idle time. And I'm sure there are other possibilities. In other words, I don't think a Facebook timeline is a modern approximation of a personal journal, and while I agree that the exposure increases vulnerability on some level, the meeting experience remains the same: using a new technological medium, we & our children try to study each others' vulnerabilities, and hide our own, not so?
More information about text formats