My method of determining if a community is "healthy" (online or otherwise) is to evaluate it after I've (temporarily) left (e.g. for the day). Do I feel angry, upset, sad? Do I feel wiser? If somebody says something I disagree with, but afterwards I find that it has brought up lots of interesting insights in my own mind, then regardless of whether I agreed with them or not, I consider it healthy.

Conversely, even if I agree a lot with what is said, if afterwards I'm angry, sad, etc. then it wasn't healthy. When younger, I used to think that more anger at what was wrong in the world, would help to fix it. Experience has taught me that actions taken out of anger, even if well-intentioned, are almost always unskillful. I want more insight, more understanding, and HN aids me in getting that far more often than, say, Facebook, which I now use only on Sundays, and not every Sunday, as a way of making sure I don't let its toxic stew of opinions infect my emotions.

I cannot honestly remember how I discovered HN, but I return because, even when I disagree with most of what is said on a topic, it is typically the case that I find my own thinking to be more nuanced or more interesting afterwards.