In the spirit of existing on Mastodon as a more complete person, I present to you .... *drum-roll* ...
My Internet forum, https://www.VeganForum.org/ ! I've been running this forum, previously under a different name, since 2012.
#Veganism is one of those things I feel strongly about. I'll leave it at that here, but happy to answer questions.
The forum has hopped between a couple of different Linux distros (Ubuntu, Debian, CentOS) and now for almost a year on #FreeBSD. And a couple of different VPS providers: Linode while running Linux, and Vultr now with FreeBSD.
I used to run a classic LAMP stack (with M=MariaDB) but now I guess it's FEMP (with E=nginx). And I've also always run my own mail system for the forum, consisting mainly of postfix and dovecot.
The forum software itself has been #Xenforo since the start. It's one of very few proprietary software products I use, but it has some great features and should rightly be credited for much of the success with the forum.
I have much to be thankful to the forum for, one thing being that my Unix server skills would never have been as good if I were never a forum admin/owner!