I half want to make a Kickstarter called "Let's Kill Facebook" that promises to give people $50 of the total proceeds to delete their Facebook account. I'd venture a surprising number of people who really care about killing Facebook would back it, and a surprising number of people who don't care that much about Facebook would take the $50. If it went viral enough to make an impact on people's networks, #3 would take care of the rest.

(I'm not actually going to do this, but it's a fun thought experiment.)