I look at announcing my real name on the Internet like consenting to a search by the police... sure, I have nothing to hide, but what benefit do I gain? None. No upside, lots of potential downsides.
Well, I disagree that there's no benefit to it. I've met lots of neat people I otherwise would not have. Actually every single mother friend I have I've met through parenting boards, directly or indirectly. I hope to set up a range day with a poster on here sometime soon (well, maybe when it's not so farking cold). My husband connected with his pistol instructor on THR, and we'll soon be taking a CPL class from him together. Yeah, there are benefits.
Of course if you're not looking for those things, that's cool. I'm just mercurial enough that if I did have an illusion on anonymity I might go and get real obnoxious when something irks me. But with my various ID's linked to my name through a simply Google search and some fiddling around online, I feel much less ready to get incautious.