I used to think traditional forums were completely dead, but after getting into working on cars I am frequently on both https://www.tacomaworld.com and https://www.e46fanatics.com
Interested to see if others hang out on SW forums or other hobbies.
It's a bit like HN in that you'll sometimes find yourself talking to people who are very famous / successful in the industry. Charlie Clouser & Butch Vig have posted there before. Best example is the thread where someone asks about Serban Ghenea's techniques (he mixed for The Weeknd, Taylor Swift, Katy Perry, Ariana Grande, Bruno Mars, Ed Sheeran etc) and by the end of the 4000+ reply thread, Serban's assistant John Hanes now replies personally every week to new questions.
https://gearspace.com/board/high-end/1213742-serban-ghenea-m...
This is particularly exacerbated by the megaforums like Reddit and this site, because whatever I may have wanted to say will usually already have been said by someone else, often more eloquently and well thought out.
This then further disengages me from most forums and after a while, I simply forget about them. Now, I only interact here, niche subreddits and a forum for locals.
(Interestingly, launched by the founder of SmugMug, Chris MacAskill. He has a great TEDx talk here: https://www.ted.com/talks/chris_macaskill_your_difference_ca...)
Mostly I'm active on r/DigitalNomad and a few of the relevant-to-me Financial Independence subs.
I imagine hobby stuff can be a little hit and miss, especially trying to find the sweet spot between a sub that's too small (with negligible community) and one that's too big (powered by too much groupthink).
https://www.team-bhp.com/forum/
It's a car enthusiast forum from India.
A handful of niche Facebook groups
Twitter (not sure if you would classify it as a "forum" ... but it can act as one)
https://www.advrider.com from time to time
not really forums, but I lurk on nixos.org matrix server