"We should try to be happy, if only to set an example." -Jacques Prévert
I try to be as open and plainly honest as possible, and I think using my real name keeps me from being inflammatory, and I think it also keeps other from doing the same to me (at least a little). Put another way, I think using real names makes an atmosphere of more empathy than otherwise.
So we should try to be sincere, if only to set an example. I think real names help with that.
Further, I try to make all my interactions on the web as public as possible. I set my Facebook privacy settings to 100% public, zero private stuff, because I don't like the state of what seems to be a selective illusion of privacy. I'd rather just be honest with myself: If I put something on the internet, it's there to stay.
[1] For posterity I use a different name for some games, because long ago someone bought a Warcraft 3 account name (Saint) as a gift, and I want to honor him, or find him again if I could, on the dim hopes he'd mention the name if he ever saw it.