I got this email based on a previous post on browser vs rich clients:

I read your comments about smart clients and Google maps. What do you think about XAML + Avalon, is it the MS’s recipe to kill HTML browser? I don’t see how it is a strategic advantage for MS, it is a replicable technology, I bet open source groups will come up with a Mozilla plug-in that is interoperable with that standards.

This question stems from a common misconception, which is that XAML is similar to HTML and is sent to the client where it is parsed and run.

In reality, XAML never leaves the server. It is compiled on the server into a .NET assembly, and that assembly is downloaded and run on the client. While this is replicable, it isn't the trivial task some people think it is.

Either you would need to replicate the .NET runtime and DirectX on the client so you could run the compiled assembly, or you'd need to build a XAML compiler on the server that generates a downloadable executable code module for your platform.

For instance, one could envision a XAML compiler that created some sort of compiled code module that could run on Linux, using OpenGL or some other 3D graphics library on that platform. But this is a non-trivial task, since XAML is designed with the assumption that the target platform has the .NET runtime and DirectX, so the compiler would need to map all the .NET and DirectX functionality into equivalents on some other target platform.

More realistically, you might envision something like mono being extended with Avalon support so it could run the pre-compiled .NET assemblies on non-Windows platforms. Even this is very non-trivial, since they’d have to not only replicate Avalon, but mediate the differences between DirectX and OpenGL or some other graphics library.

There are a couple examples of similar technologies available today. Most notably OpenLazslo and Xamalon. They illustrate the basic concept involved, which is to compile the XML into a binary, which is then transferred to the client and executed.