Comment by mtrpcic

The average comment is more in-depth because there's a long history of thoughtful moderation by people like dang. The community has learned what the bar is, and now holds itself to it (more or less). The social standards here didn't come for free, and if you were to take a random selection of the HN audience and get their Reddit profiles, I strongly suspect you'd see a notable difference in the quality of the content they post to the different platforms.