Interesting: Livejournal has just launched a Jabber server, and are developing integrated features like posting via Jabber and of course integrated Friends and Buddy lists. And they’ll be federating, so you’ll be able to talk to other Jabber-enabled systems (like GMail/GTalk) without the usual mucking about in monopoly-space (you know, like you do with AIM, MSN, Yahoo! Messenger, and all the other dark-age services that still wish it was 1990).
(Thanks to Sunyata__ for the link!)