A friend and I were discussing what it is about HN that maintains such a grip on our attention, and I realized something which is probably obvious to a lot of you: I often spend just as much time reading through and digesting the comments here as I do the original posts. It isn't uncommon for me to learn way more about the subject matter from comments than from the post itself.Are there other communities, online or off, with a similar balance between the quality of the original source material (whatever that means in context) and the responses to it? For example: an online forum dedicated to an esoteric interest; a book club or writing group; your local bicycle repair shop; etc.(A lot of workplaces probably exhibit this balance, but let's leave them out of the definition of "communities" for the purposes of this post.)