A quick thought from a guy on the product team (me) in between running around at web 2.0: We're trying to get ahead of the game with the platform here and build the foundation for the next wave of killer software + services apps/scenarios. We're already in a world where many enthusiasts and business users have at least a laptop and a smart phone, if not more devices. And we're already in a world where services are working very hard to extend to the client -- working offline, integrating with the start menu, running in their own window (vs stuck in the browser). Likewise the client guys are all making sure they can integrate with services. So from a platform perspective it's clear that the need is real today and growing in the future.
Our goal for the platform is to comprehensive (software + services, reach + rich, online + offline, etc) while still keeping it simple, open and accessible to a broad range of developers. Getting that right is not trivial. We are starting to get feedback this week at web 2.0, we'll keep getting feedback over the next several months and work quickly to iterate and get a developer CTP out there.
As for the devices we support, we demo'd Mac and WM6 live at web 2.0. We want a broad range of device support, some of it we'll build oursevles, and some of it we'll hopefully see work from the community to fill in gaps. We are betting that our focus on open standards makes community support feasible. For a hint of possibilities, see
http://www.clariusconsulting.net/blogs/kzu/archive/2008/04/24/61728.aspx .