I know some real names, or at least real first names, but I don't use them in public. I just use the pen names. Even with my family, I just say Jordan, and they know who that is. Not that I haven't said her real first name occasionally to my immediate family, but I don't think they even remember it because I use "Jordan" at least 95% of the time.
I think it's kind of cool to know the names I do, and to know alternate pen names for the same writer in a few cases, because there are a lot of them out there, too. I'm curious about others, but just in a wanting to feel like I know a bit more about the person way. It doesn't particularly matter in the long run, though, I figure. TeddyPig has had several posts on judging the writing, not the writer. In a few cases, I've seen a writer being a complete troll on the Internet, and won't get their books. It's only a few I'm aware of, though. I'm sure there are many more. One troll revealed TeddyPig's name somewhere, and TeddyPig said it wasn't that much of a secret. I think he said what it was on his blog, so it's definitely no secret anymore. So much for leverage on a troll's part.
Personally, I feel flattered when people trust me with their names, because they figure I won't use them. I use initials for real life people on here, or the pen names of online people. Some of the real life people probably wouldn't care, but I care.