We started by stating that some of us believed a while back that everything can be done with XMPP and that XMPP is good for everything. But there were cases in which XMPP was used and was problematic in particular use case.
Mostly, XMPP is just excellent for chat or instant messaging. It is good for audio as well, although it is has been developed succesfully many times (it re-uses a large amount of SIP techniques). We mentioned real-time notifications (monitoring, alerting) and social networking (Movim, Salut à Toi, Mangosta).
After that we concluded that in fact you can use XMPP for everything, but the question is rather: If XMPP is good for particular job? or is there some technology or protocol that can be a better fit?
Nobody wanted to continue this discussion, so we moved to the next point of our agenda.