Just this "demo". Makes sense considering some of the animation and interactivity they have on the small windows. I doubt the actual product uses Flash for anything other than, maybe, sound and video (as does GMail/YouTube/etc).

I'm guessing they wanted animation AND didn't want to exclude a huge percentage of viewers

If the desktop/flagship UI all flash, then they are working on an Android app as well?

Same thought too, but I think there must be a good reason for that. Maybe achieving same interactivity with html5 is just too much work yet.