This blog post cogently positions XMPP against MQ systems https://stpeter.im/index.php/2007/12/07/amqp-and-xmpp/
But now two years later, the pubsub spec makes no mention of reliable delivery to offline subscribers, and even ejabberd doesn't implement AMP, which could provide that. (Code's written, but integration appears to have been deferred indefinitely.) It is astonishingly easy to miss messages with a browser-based client. Um, have I chosen the wrong messaging technology for my app?
