This is an interesting idea. You'd have to watch out for usage spikes that would end up dropping a large number of messages (kinda like paging... I suspect thi

This is an interesting idea. You'd have to watch out for usage spikes that would end up dropping a large number of messages (kinda like paging... I suspect this gets worse quickly as the same message is sent multiple times). If you put some guards on the sending side, you might be okay (but with multiple senders this could get messy quickly). I suspect in the end you will grow this to the complexity of one of the already mentioned messaging solutions. If you don't like them perhaps something like spread (odd licensing), jabber, or irc (my personal favorite) would work for you.