In addition to everything else mentioned here, I'll add that moderation is a lot more tight and well done than most subreddits. The HN community set up an expe

In addition to everything else mentioned here, I'll add that moderation is a lot more tight and well done than most subreddits. The HN community set up an expectation early on that comments get voted down if they are of a style that encourages more noise and less substance. Sarcasm, humor, references, memes, even "nice post!" comments get voted down. This is because those type of comments are extremely easy to make and very easy to grok and vote up. Their easiness leads them to swamp out high-effort, high-content posts. The more they are tolerated, the more they are seen. This feedback loop eventually leads to a Digg-like sea of recycled garbage. HN has been inevitably slipping... But, the sea has been held back much longer than I expected already.