My understanding is that Paul Graham personally censored this website for multiple hours per day for years, and that now there is someone else, or a small team of others, doing it.
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.
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.
The internet has a public reputation as being open and free. This has never been the case. You've always had to charge for access and you've always been in danger of having your content taken down at somebody else's discretion. It used to be taken care of by your hosting company or your ISP. Now it's taken care of by Facebook, Twitter and Hacker News.
