Comment Re:XMPP (Score 1) 122
More to the point, "reliable" messaging is generally a reference (or euphemism, depending on your POV) for XA transaction support. Under XA transactions, you can combine things like database updates and queue get/puts so that they either all succeed or all fail atomically.
Not so important for IM, but rather important when the database is an order cart and the message is debiting your bank account.