Unmoderated forums have the potential to violate US law. As a result, none last for long. Even 4chan, while anonymous, has never been completely unmoderated. It has to comply with US laws on child pornography and hate speech.

There is a lot about HN's policies and the site's user-hostile features that I don't like, and occasionally complain about, but neither dang nor pg have kept the highly curated and moderated nature of Hacker News a secret. Like as not, this site just isn't supposed to be about free and open discourse, but civil, intellectually stimulating content and holding back the inevitable Eternal September effect, and many of the users here agree with that and vote in kind (and when they don't, dang stuffs the ballot.)

And to dang's credit, I follow his comments now and then and most of the times he criticizes people for their comments, they do seem to be obviously over the line.