Good points. I expect the sites which do plan to offer video via Silverlight will work it out so that the Mac users can view the video. I am not sure if DRM is always required, but I know I have viewed WMV files on my Mac before. Yesterday I watched the Fantastic Four videos with Silverlight and moved to full screen mode. It was pretty nice with a bit of a delay occasionally. That could have just been my computer since I was running a few other things.

As far as development tools it seems that Microsoft has opened up more and more to the Mono project especially with their relationship with Novell since their big announcement this past year about working together to provide better integration between Windows and Linux. Miguel de Icaza seemed to have a good week at Mix '07 last week. He has announced work will start on a Silverlight implementation for Mono has has the specs from MS. It may be a while before it is out but MS appears to be facilitating it to a degree. And remember that Mono also runs on the Mac so you could use those tools on the Mac.

Unlike Adobe Apollo or JavaFX (what we've seen of them), the Silverlight "apps" all seem to run inside the browser itself (a single process from the OS point of view). You'd think with a 15 meg footprint they would have been able to run the Silverlight apps as proper, separate entities on the box thus allowing normal application launching, switching, termination behavior to apply.

Throw in the fact that MS is locking people into their Windows-only tool chain for development, and their track record of half-hearted support for non-MS platforms (no DRMed WMV support on Mac, for example) and Silverlight looks like a pretty lousy choice from my point of view as a developer and a user.

If you write your application for the Mac using Silverlight your users will always feel like second class citizens.