Silverlight enables you to create a state-of-the-art application that has the following features:

• It is a cross-browser, cross-platform technology. It runs in all popular Web browsers, including Microsoft Internet Explorer, Mozilla Firefox, and Apple Safari, and on Microsoft Windows and Apple Mac OS X.

• It provides a consistent experience no matter where it runs.

• It is supported by a very small download that installs in seconds.

• It streams video and audio. It scales video quality to everything from mobile devices to desktop browsers to 720p HDTV video modes.

• It includes compelling graphics that users can manipulate—drag, turn, and zoom directly in the browser.

• It reads data and updates the display, but it doesn't interrupt the user by refreshing the whole page.

• Silverlight-based application with rich graphics and user interaction

• Web developers and graphics designers can create Silverlight-based applications in a variety of ways. You can use Silverlight markup to create media and graphics, and manipulate them with dynamic languages and managed code. Silverlight also enables you to use professional-quality tools like Visual Studio for coding and Microsoft Expression Blend for layout and graphic design.

Features related to Silverlight

Silverlight combines multiple technologies into a single development platform that enables you to select the right tools and the right programming language for your needs. Silverlight offers you the following features:

WPF and XAML. Silverlight includes Windows Presentation Foundation (WPF) technology, which greatly extends the elements in the browser for creating UI. WPF lets you create immersive graphics, animation, media, and other rich client features, extending browser-based UI beyond what is available with HTML alone. Extensible Application Markup Language (XAML) provides a declarative markup syntax for creating WPF elements.
Extensions to JavaScript. Silverlight provides extensions to the universal browser scripting language that provide powerful control over the browser UI, including the ability to work with WPF elements.
Cross-browser, cross-platform support. Silverlight runs the same on all popular browsers (on any platform). You can design and develop your application without having to worry about which browser or platform your users have.
Integration with existing applications. Silverlight integrates seamlessly with your existing JavaScript and ASP.NET AJAX code to complement functionality you have already created.
Access to the .NET Framework programming model and to associated tools. You can create Silverlight-based applications using dynamic languages such as managed JScript and IronPython as well as languages such as C# and Visual Basic. You can use development tools such as Visual Studio to create Silverlight-based applications.
LINQ. Silverlight includes language-integrated query (LINQ), which enables you to program data access using intuitive native syntax and strongly typed objects in .NET Framework languages.

Note:  you can integrate Silverlight with the server and client capabilities of ASP.NET that you are familiar with. You can create server-based resources in ASP.NET and use the AJAX capabilities of ASP.NET to interact with server-based resources without interrupting the user.