I was on several fitness forums back in the 00s. I think some are still around, but largely abandoned. Facebook groups, Reddit, and Discord all seem to have killed them off.

Gaia Online is still alive, believe it or not. www.gaiaonline.com

I'm pretty sure Google (and potentially other search engines) de-prioritized blogs and forums. There's plentry of both out there, although less than there were originally, they're just being cut out of some search results

All the forums I visited and participated in twenty years ago have been overrun with right clowns shouting into the void hoping to be noticed by anyone.

Similar reason why people take photos with their phone rather than a point and shoot camera, anyone can do it and it doesn't require extra work to setup.

Weird, I’ve never had issues of Reddit posts not being included in the top five results.

It’s actually the opposite issue. I’m finding in need to remove Reddit to get any meaningful results sometimes.

I know City-Data Forums is still pretty active. I've used it a lot when deciding on places to move. I'm also a bit of an urban design nerd and there's a lot of fascinating discussion I come across there.

A couple of fully active mycology forums with helpful searchable information.

I'm a member of a couple of hobby-specific forums that are still doing okay and I think there is still some life left for them. The nice part is they tend to attract subject matter experts who will answer questions from newbies without the nastiness you see on StackExchange. The small number of users and the lack of public visibility keeps a lot of trolls away. But there aren't many left. Lots of them moved to groups on Facebook or other venues where the owner no longer has to manage their own server. When they do that sometimes their archives get lost, which sucks since who knows how long social media sites will keep things or whether they'll surrender the data for someone else to archive.

Depends on the subject, though they are definitely nowhere near as popular nor used anywhere near as much as in the past. Niche groups can probably be found, but I wouldn't know too much about where to look since I usually don't go to them.

Closest I go to is Steam Underground and that is just for certain files.

There's a live discussion on https://www.twitch.tv/zeropagehomebrew right now about Atari's aquistion of AtariAge with the homebrew developers and fans in the chat. To me, it's the last of the original forums around that still feels healthy, and everyone there is just hoping it won't get killed by Atari.

Thumpertalk.com is an active forum.

There's tons of active Q&A format Discourse forums for different things that I've ran into.

Forms are definitely less active than before but they're not dead yet

There's still a lot, but they're generally niche or are more business related (eg. answers.microsoft.com). Hosting fees and technical knowledge have lead to many people just using reddit or facebook groups.

For gaming there's places like ResetEra and I think SomethingAwful still has their forums going.

There's a ton of support group like ones, often related to certain medical conditions.