From time to time I get an email offering me an invitation to join facebook. To date, I have and plan to continue to decline this invitation.
I don't remember when I first heard about facebook. I listened as friends explained to me that they were on it, that they loved it and inevitably that they wanted me to be on facebook, too.
I've never been a big Star Trek fan, but my perception of facebook is that it is somewhat like the Borg from The Next Generation series. In other words, resistance to facebook is futile.