I do what’s called a Turing Test.

I am just looking into the comment's substance. If it is genuinely interesting, I don't mind at all if it has been written by an AI or by a human.

I reported some users to the moderators where it was obvious. Either the account answered long but generic, a certain weird pattern a genuine users wouldn't do. Or multiple accounts have an agenda like trying to mention a certain product, answering each other questions. Most bots submit ads or spam though, super obvious, often dumb and auto-blocked by HN algorithms already. Bots are not allowed on HN.

How do you know it does?

Generally culture and money.

Many regular HN users care about the site and the site is professionally moderated.

An AI bot is up against a large number of motivated humans and more financial wherewithal...and some pretty good coders. Good luck.

You don't.

Currently, there is enough of an anti-AI sentiment here that people will call out what they believe to be AI generated content, and most of the time commenters will preface such comments, and they will get voted down. Such comments are becoming more and more common, however.

But plenty of HN users are pro-AI, or work for AI companies or have AI startups, and of course this forum is run by the company formerly owned by Sam Altman. I strongly suspect (but can't prove) that there are already AI driven accounts here, and that people are posting AI comments without bothering to mention it. And that the trend will grow in that direction over time as AI becomes normalized within the tech industry and society at large.