There are those applications that Facebook leaves to the developers, and others that Facebook feel are integral to the operations of its core functions on its growing social network. Webware reports that Facebook will soon be adding an instant messaging application that users can embed on their profiles, in the coming weeks. There aren't many details that have been released on the upcoming instant messaging application, but one thing is clear--its introduction will raise several questions for those third-party IM clients that have built into Facebook's platform.
It's not so much that chat is being added to other applications (though this is the literal case), but that chat is an inherent activity that takes place amongst human beings, and new standards are being developed for improved integration of other activities that could benefit from the perk of immediate chat. One thing I'm curious about seeing is how a stationary profile chat window will be most useful for Facebook members, and if it will be integrated with other IM clients.
Reports of Jabber-powered chat have surfaced, but these have yet to be confirmed. Knowing Facebook and its end goals, I imagine such integrated chat will also have some in-move for leveraging of the Facebook social graph, and any use it could have for providing chat to Facebook applications could also be something to think about, as we await the details from Facebook itself.