So then the question that follows is how do you prevent any niche gathering, digital or real world, from becoming an echo chamber? Don't all like-minded groups eventually become echo chambers? Even HN runs a risk of becoming an echo chamber as a group of like-minded people that quickly popularize a news story and then comment/respond in similar fashion.

I'm not saying that to bash HN. I love HN. I learn more from the stories and comments than any other source. I think "regular news" (RN?) is mostly a mix of garbage and entertainment. I like having like-minded individuals to learn from. I don't want to spend time in groups that talk about which Hollywood celebrity of the month is getting married/divorced/hired/fired/honored/dissed.

I think a diversity of participants, diversity of opinion, and diversity of passions is a good start. I think we have that here (even if in a somewhat narrow slice of diversity). After that, do we just hope for the best?