Also it tends to shut up exactly the disadvantaged people we want to here from. Personally, I use my real name, but I'm a white heterosexual male. Change any of those and I might not feel so comfortable giving random strangers the means to find me. My fiancee for instance avoids using her real name like the plague of death.
I kid, but this is one of the best discussions sites on the web, and few, if any, use their real names here. Clearly discussion quality is much more significantly determined by other factors: site demographics, culture, subject matter, even the UX of posting in and viewing discussion threads probably all matter more than whether people use real names or pseudonyms.
Using pseudonyms has been traditional online for a very, very long time, and it's possible that some of the unique aspects of the internet as a social medium might not exist were this not the case.
Much of this discussion revolves around anonymity, but it's important to note that people who consistently use the same pseudonyms in the same communities are not anonymous within those communities. But by using pseudonyms, they're able to de-link participation in one community from their participation in other communites - including their offline relationships - and posit a context-specific persona.
The old "on the internet no one knows you're a dog" cartoon comes to mind, and not just because of your comments about being a "white heterosexual male", and that being in other categories might expose you to certain risks; you're also able to start with a blank slate in a new community, or start over in an old one, and have your identity there be shaped entirely by the value of your participation. You don't get this anywhere else in life.
I'd be surprised if most of the people posting cogent and insightful comments here on HN aren't also posting the occasional image macro on Reddit, or posting God-knows-what to 4chan, or participating in forums, IRC channels, etc. under names that keep their identities on these disparate sites quite separate, and adhering to the cultural norms of each within its own boundaries.
I use a fake name specifically because I'm a white heterosexual male. You don't seem to understand which views are verboten and punishable in this modern age.
Speaking as a white hetero male, we're the safest demographic on the web. Just because we get some static doesn't mean that other demographics are better off.
