There are a number of open source events, projects, and foundations that primarily communicate on Matrix, and no surprise it seems particularly common among projects that build on federated technologies (eg ActivityPub-based projects). That's what got me started on Matrix before I joined to lead the Matrix.org Foundation :)

The thing is even though not all communities were fully there, they were using the bridges. As far as I know almost all KDE and openSUSE channels were bridged. Now we ended up with a situation where there are still people in the matrix rooms with no connection to the irc users.

I mostly use it for the Fedwiki and NixOS community channels.

RedoxOS uses Matrix for their chats now.

Neovim, especially now that they no longer maintain their own bridge to Libera.

Oh good to know. That's one I would hang out in. Thanks.

Seattle social groups, NixOS

Boiling Steam on Matrix.org for Linux gaming

You aren't. If you haven't heard of social media it lacks sociability: it's only feature. If you want information join mailing lists. Discord and IG is what I usually use; because and only because everyone else uses it.

All of the fedora.im rooms.

Opensuse also has their own matrix server #space.opnensuse.org and archlinux does too #archlinux:archlinux.org

The bridge drop affected Fedora quite a bit - Fedora traditionally used to have their IRC rooms on freenode, then on libera.chat - including the "official" stuff like Special Interest Group meeting, bug triages, GO/NOGO meeting for release, releng, etc.

While it was decided to migrate to Matrix, still a lot of tooling was built for IRC & many users connected via IRC to the rooms, so the situation with bridges in place was ideal.

But wen the bridge stopped working, it effectively split some of these room in half, with some people being on Matrix and some only on IRC. Worse yet, some meeting still depend on IRC only tooling/bots & happen only on the "IRC side" until the tooling can be ported. Not the best situation. :)

F-droid,All the privacy frontends like invidious, piped, nitter, searxng, libreddit

Mozilla; CCCamp.