A kind of site that was probably well known to most in the early 2000s and later was the forum. Threads could go on for years, and responses could be incredibly in depth.
Are there any active sites like that today?
My answer to your question is, other than HN, probably nothing else is reasonable.
While HN is mostly by and for coding peoples, it oft provides interesting discussions of engineering, science, and society. My remaining favorite discussion forums are densely technical and increasingly narrow in scope, so would not meet your requirements.
A lot of car forums survived redditification, probably because those communities are run by car enthusiasts who passionately care about every detail and would never surrender control to a benevolent central authority just so that they don't have to do slightly more work maintaining the site than they otherwise would have.
Search for almost any popular sports car and you're sure to find extremely popular forums that date back to either the early days of the internet or when the manufacturer started production.
I do wonder if there is value in having basic interfaces. This combined with tech focus seem to have created 2 of the better discussions/information sites IMO (whirlpool and HN).
While a bit more domain specific, webmaster world used to be good, still might be but I haven't been visiting for a couple of years: https://www.webmasterworld.com/
- I am the creator.
- It is a link aggregation site like Reddit and HN, but the link field is optional.
- Threads are never closed.
- No front-end JavaScript.
- No voting.
- There are actually no admins or moderators. Instead we show nothing by default and users must whitelist other users.
- Open source: https://github.com/ferg1e/peaches-n-stink
- This probably sounds like a crazy site but it appears to be working and I've had some nice convos with some of the users.
Lots of open source project use it as web ui for mailing list