Silverlight 3.0 Released, Allows Apps Outside the Browser
Many different sources are reporting that Microsoft has unleashed the third major version of Silverlight to the masses. With 3.0 we see things like better 3D graphics support, the ability to offload tasks to a GPU, and the ability to run apps outside of the browser. "Silverlight's video capabilities have always been impressive when compared to Flash, and the new version boasts some new features that should keep the competition with Flash hot. It uses a media broadcasting technology Microsoft calls Smooth Streaming, an adaptive technology for playing the same H.264 video stream at the highest bitrate the device and its bandwidth limitations will allow. So if you've got a fast computer with an HD monitor and a wide open pipe, you'll see super high quality video at up to full 1080p HD. If you've got a dinky smartphone with mid-level data service, you'll see a constrained version of the same video."
I dont think multiplatform (or the lack of it) actually does a lot in competition sense. There is a Mac version of Silverlight too, and linux is quite minority market. Main problem for Silverlight is how to get more sites use it instead of Flash, and this is where the advanced features and good developing tools come in and I think MS understands that seeing how they keep developing them all the time.