I'm the opposite here I find. In my day to day life I'm pretty much an open book, but the internet is a much more dangerous place. Sure you guys all rock, but this is an open forum that anyone can stumble on. The fact that people know I live in Toronto kind of weirds me out.
That coupled with the fact that I write books for kids means I am much more careful with my word choices. I don't swear here really at all, compared with my everyday life, nor do I go into deep details about my love life. I only share thoughts etc that I would be willing to see in print in a newspaper somewhere. I think there have been one or two instances where I have regretted a post in that respect and so either edited it or removed it.
People can find you, if you google my book title then you can find my posts here, if you put two and two together someone, if they really wanted to (though why they would I have no idea) could read all of "Toothpaste"'s posts. Some people here are totally anonymous (well as anonymous as IP addresses will allow you) so that gives them a little more freedom, I have far too many identifying features on this site.
For that reason, I am extra careful. For that reason too I think people are often surprised what I am like in person vs on the net when I meet them face to face. Not to say I'm not being me here! That's one of the lovely things about this site, people seem to accept you for who you are. But a much more careful me.