I use my real name. Have for a long time. The main reason is I'm too lazy to do otherwise. Privacy is hard work. And you only have to fuck up once for the whole thing to come tumbling down: forget to log out of one account and post something under the wrong name and your anonymity is toast.
The other part of it is that if you look at politicians who have gotten caught, it's always the cover up that kills their career rather than the original offence.
My preference for real names stems not from some idea that it makes us better people (I've been in real-name-only communities and there's absolutely vicious, horrible people who participate and are just fine with their vicious horrible nastiness being attached to their real name, because they consider that a small price to pay for being mean). And sometimes real names means there are negative consequences for me: I'm a Wikipedia admin and because I use my real name as my username, there are certain tasks I just don't go anywhere near because I've seen the doxxing and other shit that's gone on to other people. And mostly my fellow admins are fine: they understand why I don't want to deal with certain people—there's plenty of other people who can deal with the stuff that I'm not inclined to handle.
No, there's a much better reason for it. I've done secrecy in the past. Nearly a decade of it: it's called being gay and in the closet. And it really is a fucking waste of life. It makes you utterly miserable. Coming out is a huge psychological relief. Ten years of fear of other people's judgements is a long time to put off having relationships and, well, life in general. The misery of the closet made me make decisions about my academic/professional career that I have come to regret too. But to come out, you need to reach the stage where you don't really give a fuck what someone thinks about you. That comes with age and maturity and self-confidence.
The reason I'm open about my life is that I've tried the alternative and it didn't work out for me on a pretty epic scale. There's something very freeing about being very open about life and not giving a shit what people think.
When you've successfully left one closet, building new closets to hang out in starts to seem like a very bad idea. Sure, people might judge me negatively based on what I say. But they might judge me negatively simply based on who I am. I don't care enough about their opinion of me to not live openly and speak the truth as I see it.
I wrote a long-ish post about this kind of thing recently: http://tommorris.org/posts/8268