CIRCLE WITH A DOT

@lina
A lot of it seems inherit to a selling point that is (afaik) unique to matrix: group chats not being tied to a single server. All participating servers are equal on the protocol level.
This means that a group chat can survive the server it was created on going away just fine (unlike XMPP) which is a great feature to have.
But it comes at the cost of complex state resolution issues, since there isn't a single source of truth, and every participating server might have different ideas about basic things like "what users are currently in the room".
@jacksonchen666