photosynth is cool... I've played around with it at times and it would be a useful "tool in the toolbox".

I haven't seen any stats on how well distributed silverlight has become... so it's impact will be somewhat limited to viewers that are either out on the front of trying new tech... or don't care what plugins get loaded into the browsers. Maybe when MS comes up with the "killer app" that is silverlight based, we might see a surge in it's installation base.