From CES: Yahoo Messenger on WPF

Check out this video of what Yahoo is doing with the Windows Presentation Foundation.  They've rebuilt their instant messenger to use the new presentation foundation in Vista.  It's an example of the type of next-gen application user experience that is going to be possible and commonplace now that WPF is out there.

https://www.on10.net/Blogs/larry/yahoo-messenger-on-wpf/

Note to the Windows Live Messenger team:  I hope you're taking notes for version 9!