And Slack/Discord are not good examples. You're just setting yourself up for a world of monetized walled garden hurt long term. Matrix however is pretty great.

Like the article stated joining a community of like minded people brought a feeling and discourse that I don't really get on modern commercially hosted platforms that offer a "one size fits all" solution.

https://www.lfgss.com/ is one example of about 300 sites that are using the platform.

It's recognisably a forum, but works great on small screen devices and includes richer functionality such as events within forums (logically forums are more equivalent to folders that can contain differently structured things, so not just conversations but events as well for example).

I'm still tempted to work on it at times (hasn't been updated in many years) but for that to be a motivation I'd want to believe that others would run instances too and it would grow as a self-hosted multi-tenant option.

It's extraordinarily cheap to run, far less maintenance than any other forum platform I've ever operated.

Discourse is interesting, it allows you to view threads by category, or by a feed where the most recent discussions appear first. Both have social media like features such as status updates and posting on peoples profiles.

Platform as in software-that-you-install-somewhere (in that case: Discourse seems plenty modern for me) or platform as in forum-as-a-service that will most probably end up with a dubious monetization scheme ?