Facebook Groups tripped up by the old opt-out problem
So we know Facebook set up this new thing where you can make groups and sort your friends into those groups. The idea is that you can keep your work friends separate from your family. But those additions and those group NAMES are publicly visible. So it didn't take long before someone added Mark Zuckerberg to the NAMBLA group. Since then, that group has gotten a lot of other names who are then associated with NAMBLA. If any of you reading this are my Facebook friends, I can add you to it right now and then it's up to you to go back in and opt out. Nice.
Obviously, Facebook could change Groups so it's more of an invitation/accepted invitation type of construct. And maybe the negative publicity they're getting from this will force them to do that. But that would mean a pile of invitations to sort through on Facebook that, let's face it, you will never get to. And I doubt they would want to do that.