@kaia @georgia they don't have a space/guild with subchannels analog like matrix or discord.
But it's basically group chat/direct messaging that is e2ee. You sign up with a server but the account is portable between them, with the server just providing a relay (it's email under the hood).
It's like xmpp if e2ee worked, or sms if it weren't shit. Very appropriate for your family or personal communication imo.
I'd say it's closest to signal or telegram without the sms requirements