MMS pre-dates iMessage, but even today MMS does not support persistent multi-party group chats. You can create a group MMS, but it's stateless; you can't chang

MMS pre-dates iMessage, but even today MMS does not support persistent multi-party group chats. You can create a group MMS, but it's stateless; you can't change the membership in any way without creating a new entry in your chat list; this naturally fractures the community (people using old group chats instead of the one with the current membership, etc.) The specific implementation details do matter; and I think that this fundamental weakness of MMS has created the space for WhatsApp, iMessage, etc to thrive.