Yes, I must second this. The quality of conversation on HN is simply put... amazing. It boils down to the people that you choose to associate with.

Think of your Facebook friends. I seldom talk to my "friends" there so it would make sense that the content they produce is usually of very little value. Most times Facebook makes me aware of internet memes and that is about it.

I've seen plenty of attempts to transplant the HN 'spirit' to other verticals (HN Europe comes to mind) but until now the kind of self-discipline that makes HN tick doesn't seem to translate well to more mainstream niches.