It is the most amazing thing evar!
I have been using it internally for the past couple of months. You use your IM program to chat with people on your friends list. Its amazing how time flies when I can chop it up with my guildmates in CO and STO while answering tickets.
Yes we have turned off the XMPP for now. It will be turned back on when we don't think it is what has been crashing the global chat server.
One of my friends who was logged into the XMPP connection when the system crashed still shows as logged in even though she's no longer connected. It's suppressing the login/logoff friendslist messages, too. Maybe something is still messed up in the XMPP access even though it's been turned off?