WPF/E rechristened Microsoft Silverlight
Silverlight is a cross-browser, cross-platform plug-in for delivering
the next generation of media experiences and rich interactive
applications (RIAs) for the Web. Silverlight integrates with existing
Web applications. Silverlight media capabilities include fast,
cost-effective delivery of high-quality audio and video to all major
browsers including Mozilla Firefox, Apple Safari, and Windows Internet
Explorer running on the Macintosh or on Microsoft Windows. By using
Microsoft Expression Studio and Microsoft Visual Studio, designers and
developers can collaborate more effectively by using the skills they
have today to light up the Web of tomorrow.
https://www.microsoft.com/silverlight/default_01.aspx
Silverlight (previously codenamed "WPF/E") is a lightweight subset of XAML for building rich media experiences on the web.