This is a very good analysis, and is why my Facebook account is currently deactivated, and probably will be deleted. Contrary to Matt, I don't find Facebook very useful. Mostly it's served me to be found by people by whom I wasn't all that interested in being found, to see relatives' photos (which I can also receive through other means), to be endlessly spammed by people playing Farmville and, most usefully, to contact people whose email addresses I don't have or can't bother to remember. None of these are indispensable or irreplaceable to me.
I have a significant online presence, so if someone is interested, I'm really easy to find. I'm just not comfortable with having to keep tabs of what Facebook is doing so I can go tweak my settings every time they decide to change something.