I've noticed a pretty significant uptick in new accounts posting complete garbage. I don't mean the comments are bad, they're not even words in many cases.

I collected a few of them: https://news.ycombinator.com/item?id=47130684

But it also seems some topics (in particular AI) attract a lot of accounts that post incredibly low quality comments, far below the quality you'd expect from HN. Ofte it's in reasonable English, but it's just inane reddit-level drivel. Unclear if these topics attract low quality posters, or if these are bot accounts.

Also looking at the three first pages of /noobcomments, we find 28 comments with EM-dashes in them. That's not proof of AI, but if you compare with /newcomments, you find exactly one EM-dash going back as far. That's a bit of a statistical aberration.

I believe it's the former, which of course does not exclude the latter.

It's likely people with mediocre ideas but access to free LLM tools are able to get over the care-risk-reward activation energy and consequently submit their ideas with the help of LLMs.