Roundup/Services
XMPP Roundup: services
Facebook Chat on XMPP
http://blog.facebook.com/blog.php?post=297991732130 http://wiki.developers.facebook.com/index.php/Integrating_with_Facebook_Chat http://www.facebook.com/sitetour/chat.php
RSS.IM
IMO.IM
By an ex-Googler https://imo.im/
Tigase.im
Jappix
Jabber.me
livefyre.com
http://livefyre.com/ for cross-domain, cross-blog commenting in real time over XMPP.
After Facebook, Vkontakte
The Russian Vkontakte social network is using XMPP as the basis of their chat system, enabling third party clients to connect.