Because I, and millions of others, will not be able to use them. That’s because we use 64-bit versions of Windows.
You see, the Windows Sidebar uses Internet Explorer to host the HTML and script that make up a gadget. On 64-bit versions of Windows, the Sidebar is a 64-bit process, and so it uses the 64-bit version of IE.
There is no Flash or Silverlight for the 64-bit version of IE.
About a week ago I encountered a gadget offering from MSNBC having to do with the presidential primary results. I added it, only to find that the gadget’s UI was totally missing. It didn’t take long to figure out they were hosting Flash.
I’m actually quite disappointed at the lack of 64-bit Silverlight support, as I believe it would be a compelling solution for gadget authors. .NET already works great in gadget situations because it gets compiled at runtime for the appropriate platform - and thus works on both 32-bit and 64-bit versions of Vista. I had hoped that since Silverlight is based on .NET that it would include similar write-once deploy-anywhere support, including 64-bit platforms.
I hope that is something they fix in the near future.
Update: Yes, you can install both Flash and Silverlight (1.0 and 2.0) on Vista x64 systems. I assume that everybody knows that, but perhaps they do not. The caveat, and point of this post, is that you are installing the 32-bit version of Flash / Silverlight, and thus it only works in 32-bit applications. The default browser on 64-bit Windows is the 32-bit version of IE, so these plug-ins work fine for web browsing. But they don’t work in the sidebar, or any 64-bit applications that host IE.
