A brave soul by the name of Todd Vierling has posted a compelling opinion piece explaining why, in his words,
… those of you who think that using real names will make people more open and social are horrifyingly deluded. Your idealistic vision of “real” interaction through real names isn’t just nonsense; it’s making online socialization more dangerous for everyone by putting them at risk of real-world prejudicial action.
It’s worth reading. I suggest that you do.