About 6 months ago I stopped using Facebook on a regular basis and basically made it into what my MySpace page does: someone could potentially still get in touch with me. When I made this decision, I was worried that they would hit sort of an idiot threshold and start backing down from a lot of bad anti-user behavior. Then I would have felt stupid for basically quitting the service. Fortunately, my decision to leave has been continuously and constantly reinforced, including by their latest move to edit all your contacts' email addresses.
Which is good because every time it gets worse, I feel better.