Nombo UG wrote
peer to peer
user to user
intant message
Private message
I see at least three requests in one — P2P is something that may be complemented by instant and/or private messaging.
There are many instant messaging systems that fulfil all three requirements.
Rather than re-invent the wheel within Nabble — create yet another messaging system — I would tend towards a technology that enables users of Nabble to use existing messaging systems.
Regards
Graham