As stated above, it's a security nightmare.. IRC discloses potentially revealing information about guests, but in a XMPP conference.. your identity is safe by default.
What does this mean? nobody except moderators can see your full jabber ID, private messaging is even restricted.. of coarse, that may or may not be handy.
I just like the Jabber/XMPP protocol.. and I really like advocating it, far too many bad IRC experiences.
