New features in Silverlight 3 include the addition of H.264/AAC codec support and "Smooth Streaming" which "dynamically detects and seamlessly switches, in real time, the video quality of a media file delivered to Silverlight based on local bandwidth and CPU conditions." Full-screen resolutions up to 720p are supported with GPU hardware acceleration. Additional feature details and a download of the plug-in are available from Microsoft's website (Intel-only).
Silverlight has made some inroads since being launched in 2007, with Netflix using the technology to deliver streaming video content to PCs and Macs. Other big-name providers using Silverlight include NBC, Tata Motors, and Continental Airlines. Microsoft provides runtimes for Windows, Mac, and Linux, however development is limited to Windows platforms.
While Silverlight competes mostly with Adobe's Flash, Apple has been working to blunt the impact of such technologies with their efforts on standards-based HTML5 and today's news of 3D CSS effects in Snow Leopard's Safari.