Having followed XMPP since it's inception in 1999 and developed software around the platform, I can see some widespread activity in the greater web, rather than just discreet deployments as an IM platform.

The XMPP community is talking about social networks and how XMPP could have a role in connecting these in a pub-sub fashion. An interesting article (spotted by Tamir) on Social Media Today points towards this type of connectivity.