In the editor you select a service, and then whatever's relevant to the service of: username, password, server, room
View mode is the live chat.
Embed irc:freenode.net/#wagn in the sidebar!
(default username to their sign-in name unless they edit the card)
This can already be done the hard way, with HTML cards.
instant messaging cardtype+discussed in support tickets
instant messaging cardtype+relevant user stories