Most things work fine, such as two-person chats, sending graphics and map extents, etc. However, the chatrooms don't work. Dashboard can create new rooms, but messages typed in them never get displayed, and two users in the same room can't see each other.
It seems that Dashboard's implementation of XMPP MUC (Multi-User Chat) isn't compatible with either of the servers I've tested. I attended the Holistic Testing session for Dashboard back in October and was told there's a proprietary chat library client-side. Do Esri recommend a particular chat server, and if so could this information be displayed in the online help?