People keeps comparing those services. I don’t get it. They’re completely different. Twitter is an open conversation and a place where you meet new friends. Facebook is a closed conversation and a place where you meet old friends.
I just did a quick count. On twitter I follow 299 people. And 37 of them are friends to the level that I would have said hello if I met them on the street. On Facebook 151 of my 200 friends are at the same level.
That said. Currently I rarely visit Facebook. And I use Twitter all day long.