Discord servers seem to be the place where it is happening right now. There are still some community forums, and maybe Facebook groups. On a more public scale, there are some well managed subreddits.
Edit: Plus the oldschool, geeky stuff like BBS, usenet, mailing lists, IRC etc... that still exist but are usually limited to technical people and subjects.
Hey, I'm currently building a website that I think would fit well with what you're looking for. It's called Reason, and it's designed to help find small (3-10 users per chat or so) group chats about the topics you're interested in. I started working on this specifically because the casual, small places to meet like-minded people on the internet have kind of disappeared.
http://www.reason.so/
Make sure you post it to Show HM when it's ready, I would definitely check it out.
Re:I Miss the Old Internet (2019)
by Apocryphon on Sunday June 13, 2021 @01:27PM
(#27494399)
BBS forums are still in abundance. Many of them seem relatively clunkier now and are niche, but they exist. And they all end up starting Discord servers.
But where? The venues where that happened are gone. You can have a public discussion with 100.000 eyeballs, but not the kind of more intimate, local environment that were earlier boards and chat rooms.