As a way for people to talk about unimportant topics, small talk serves a few vital functions: 1. it allows politeness without deepening the relationship. 2.

As a way for people to talk about unimportant topics, small talk serves a few vital functions: 1. it allows politeness without deepening the relationship. 2. it can be a breadth-first search of mutually-stimulating topics for in-depth conversation (which may lead to a deeper relationship if desired). 3. it can avoid accidentally offending someone with controversial topics or opinions. 4. is quick to disengage from, unlike a story or debate, so is useful as a conversational holding pattern. HN doesn't really fit any of those. Sure, some comments will say "my kid does this", but I find they're rare on HN (and usually downvoted); in general, comments are adding new data or engaging in debate.