The longer I'm on Facebook, the more I'm missing the absence of groups in Mastodon. It's a really nice feature to have. Microblogging is nice but it's also nice to have a centralized place for discussion.
@tealturtle have you tried #Friendica or #Hubzilla? These have groups that federate over #DFRN and #Zot respectively (disclaimer: haven't tried them myself). Like federated events, federated groups is a passion for me too. Maybe we could create a board or thread on the new #SocialHub and try to get reps from AP projects that have some kind of groups feature, to discuss interop?