Doesn't Silverlight browser support seem ubiquitous?
We used Adobe Flex for a large project, but it's too slow.
We are planning to migrate to Silverlight.
The problem is that Silverlight is not as widely supported by browsers as Flex / Flash.
For example, I tried to access the Silverlight Storefront using Safari for Windows, but it didn't work.
The RIA web platform surely needs to have a general browser ubiquity?
Browser plugins are essentially native applications, so you need a plugin for each architecture.
For example, there is no 64-bit Flash plugin for Windows, so I always have to use 32-bit IE for this. I also believe there is no Linux-PPC support, but it has been a while since I looked at this. And this new JavaFX stuff from Sun also doesn't work on many platforms and browsers.
For a list of supported platforms, Wikipedia has a neat table:
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