I have observed (empirically) that independent of the platform or specific type of content, all it takes for an discussion to get ugly/ irrelevant is a handful of comments that are beside the point or funny. I realize that the extent of disarray depends on factors such as moderation, vote/rank systems, etc. But I was wondering if there is an analogue of the broken windows theory for this phenomenon?
It's bikeshedding. It's easier for any given person to comment on the joke or insult or cultural reference than the main subject, and the extra comments derail the discussion.