I'm not involved with HN, but it seems likely that many smaller venues esp ones that aren't big money makers, including most mailing lists and small sites like HN would be advised to discontinue operating if exposed to this kind of extraordinary liability over content which they had no knowledge of.

"Actual knowledge" should be your preferred approach to your concern... but nothing will probably solve your problem because extremely well funded platforms are substantially immune to the law in any case, just as they're immune to common decency.

No, they’re not social network type services like Facebook or Twitter, but... section 230 doesn’t discriminate between types of online services!

It's not all chatrooms and social media. Restricting the internet to be run by people able to manage their own websites would hurt. Ebay would have to manually review every account and listing. Good luck finding a user review website like Rotten Tomatoes. No more Straw Polls. No more GitHub.

It goes deeper than that, I think. Do VM hosting companies also rely on Section 230 immunity? Do ISPs? (They’re not Title II common carriers anymore!) Would providers of this nature be required to monitor what their users do as well?

I don’t believe either of these have been tested in court, but I think there’s at least the potential here to make it much, much harder to manage a website.

And automated systems have their own huge problems.

Fixed that for you.