Microsoft Silverlight is a cross-browser, cross-platform plug-in for delivering the next generation of Microsoft .NET–based media experiences and rich interactive applications for the Web. In short this is Microsoft's answer to flash.
We do fully support it as it is a client side and not a server side plugin. This means
the end user must install a browser plugin to view a SilverLight site and nothing must be installed on the server
Silverlight works with any Web server just like HTML does. Video and audio content can also be progressively downloaded and played back from any Web server platform. Benefits of Windows server-based distribution of Silverlight applications include Windows Media Services with Fast Stream (instant playback) and Fast reconnect technologies, lower distribution costs (streaming users only download what they watch), and tap into the full Windows server ecosystem of platform components and partner solutions. Those benefits will be enhanced in the future version of Windows Server 2008 and with IIS 7.0.
You will need to add a MIME type to your domain in order to support SilverLight. Please see: http://support.webecs.com/KB/a224/how-to-enable-silverlight-support-in-helm.aspx