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.Silverlight offers a flexible programming model that supports JavaScript, .NET, and other languages.

you can use in addition to silverlight project and .net framework some design tools like Expression blend and Microsoft Expression Media which all are interconnected with each other which helps creating user interaction for the application that you are working on:

- Expression Media which allows you to create and enhance videos ;
- Blend which is a design tool to create user interaction for Silverlight.

It is very useful for media project,GUI animations it simplifies the work to add animation in your application.

One of the projects done with Silverlight is the Top Banana which is a great media application that enables you to sort browse and edit video content.It is a rich interactive application deployed online and viewed in the Browsers(Firefox ,IE).More over you can drag the video player to transform the video frame into a sequence of images visually representing the entire video this is called film strip mode. All these edits that u make to these videos are finally stored as XML and with windows media you can publish the video in a blog ,website or broadcast the video.