[Standards] Presence problem in large MUC rooms.

Hi, Following what I've said yesterday at the summit, I would like to explain more my idea, and get your feedback. So basically the problem with presence in large MUC is that we get 2 things: - initial presence when we join the room - all the presence update when people join and leave, which is quite often with people on mobiles. So my point was that we are seeing MUC by the way it's used today. But we don't have to. We don't have to be actively in the room. What we want when we are in a large room, is to be able to check it when we want, and be notified when we are mentioned. For smaller rooms, we may want to be notified on each new message. The way I see it, we could have 2 ways to join a MUC: active and passive. The active join would be what we do today, we get all the presence, and updates, it's really bandwidth intensive. The passive join, on the other hand, would only say "we are in the room". The MUC service would then notify the client only in case of mention (or for any message in case of "subscribed" room). Benefit: - we don't have presence spam anymore, the client does an active join only when the user want to actually be in the room. So it's only one room at the time. - client doesn't have to actively parse message to look for mention, on mobile it will get a push notification and wake up only when necessary - It should be easy to implement on top on existing MUC implementation - It's backward compatible: non-compatible client will just to "active" join all the time, and get all the presence spam. Probably we can also optimize the initial presence in case of active join, but that's another topic. I think that solves the presence issue. Let me know what you think about it. Best, Goffi