Based on the recent Adobe and Microsoft announcements, I expect most Flash and Silverlight Web developers are now thinking about how they'll move to Web standards. This is a good thing, but there are still features in those plugins that are missing from Web standards. One big feature is DRM for video. The problem is that some big content providers insist on onerous DRM that necessarily violates some of our open Web principles (such as Web content being equally usable on any platform, based on royalty-free standards, and those standards being implementable in free software).
We will probably get into a situation where Web video distributors will be desperate for an in-browser strong DRM solution ASAP, and most browser vendors (who don't care all that much about those principles) will step up to give them whatever they want, leaving Mozilla in another difficult position. I wish I could see a reasonable solution, but right now I can't. It seems even harder than the codec problem.
I am curious about what IE10 will do in this area. If Windows 8 Metro IE10 doesn't support Flash or Silverlight (as Microsoft says), and they don't support a strong DRM solution (and I haven't heard they will, yet), how will distributors of expensive HD content satisfy their DRM requirements and play back in Windows 8 Metro IE10?