Silverlight is often referred to as Microsoft's Flash.  Microsoft needed a cross-platform cross-browser implementation of the .NET Framework for building and delivering next generation media experiences and Rich Interactive Applications (RIA) for the web.  Playing WMV video, MP3 and WMA audio, progressively downloading & streaming media , vector drawing and animations, etc are all supported by Silverlight.

Developers can write Silverlight applications in any .NET language and/or they can write them in entirely in XAML.  Silverlight integrates seamlessly with Javascript and ASP.NET AJAX.  For instance, a Silverlight function can call a Javascript function and vice versa.  Silverlight is also delivered to the browser in XAML.  This is interesting to me because search engines can then crawl the Silverlight object's XAML.  Therefore Silverlight application content can be easily indexed by search engines and thus are more findable than Adobe Flash movie content.

I plan to start developing with Silverlight in the near future.  I'll be blogging on my experiences as time permits.