So Facebook Chat now uses XMPP. And the Empathy development version has some nice integration.
This could mean that I can finally chat to non-Jabber using friends on a regular basis. It's been nearly four years since I switched from MSN to Jabber, and I think I lost contact with a lot of people. Facebook chat via AJAX is unreliable, and my visits to the site are quite irregular, so hopefully this will work around both problems.
I for one welcome our social network monopoly overlords…