Yup - I'm well aware - and the barrier to entry for HN is pretty much non-existent. Some features are locked behind karma accumulation but most of the moderation is done manually and the community is small(ish) enough and of a professional bent - meaning that a lot of people know who other folks are IRL. Removing the anonymous factor for a large portion of commenters makes them follow the rules a lot better.
There still are lots of issues with smurf accounts though, again, there's a sort of barrier to entry in that extremely new and low karma accounts can get their comments [dead]'d very trivially.
