The forum experience is dying. I spent about 4 years of my time in-between Google stints working on a searchable feed for forum sites. Finally gave it up when I realize the extent to which the forum scene had died and moved to Reddit & Facebook while I was working on the project.

The root problem is that attention has gone from abundant to scarce, and people already have their habits. That makes it really hard to build a new forum site and attract an audience that's willing to type your URL in every day (and if they don't visit daily, forget about building a viable community). Forum hosts like Facebook and Reddit don't have this problem - you can view your Buy Nothing Group and Moms of Springfield posts interspersed with your feed of friends, or your r/factorio content interspersed with a steady stream of r/AskReddit.

There's also emerging technological barriers. If you don't sign up for CloudFlare, as a new website, you're going to get hosed - but at the same time, CloudFlare makes it basically impossible for any new search engine other than Google to spider the site. Ditto security patches, and keeping software up-to-date. Most people don't want to deal with sysadmin stuff at all, particularly if they're trying to build a community as a hobby. So that pushes people further toward hosted solutions with a turn-key secure software stack, which is Facebook and Reddit.