#Smithereen update. Groups are more-or-less done, as a proof of concept. They should federate in theory, but I haven't tested any of it yet because I'm too lazy to set up a second internet-facing instance and Mastodon isn't very much compatible with what I'm doing here.
That said, there's still a lot of work ahead. Admin/moderator features, public admin list, events, invitations...
You can actually try joining the group by following it from any ActivityPub server: @wow_look_a_group, but it doesn't post anything itself so nothing will show up in your feed. It works by forwarding LD-signed activities of people posting things on the wall. Oh, and I should make /groups/X/wall return a real collection of posts. And then will be the time to write my FEP about publicly-appendable collections.