There are many active discussion venues for Jabber/XMPP developers, system administrators, and end users. These lists are all easily searchable at www.mail-archive.com.
For System Admins
Operators@xmpp.org email list — for discussion about day-to-day operation of the Jabber/XMPP communications network (subscribe | archives)
For Developers
Standards@xmpp.org email list — for general discussion about XMPP protocols (subscribe | archives)
xmpp@ietf.org email list — official list for XMPP Working Group discussions at the IETF (subscribe | archives)
For Members
Members@xmpp.org email list — official list for members of the XSF. Subscription is available for members only, but the archives can be found here.
All of these venues are completely free and open to any interested individual.
