I don't use twitter, but downloaded to see that zune UI. You guys did awesome job, really like how smooth it all works. How long did you guys cook this thing? Did you follow any ui guidelines or just copied zune software feel?
We definitely looked at the Zune desktop UI as the starting point to do a Metro-like experience in a desktop client. We also draw a lot of inspiration from the Metro guidelines on WP7S, but obviously not all of that is applicable on the desktop.
In areas like the notifications, we're trying some UX concepts of our own with the "Metro" philosophy in mind.