Microsoft's confinement to its Silverlight plushy Internet plug-in document

Silverlight 5 includes hardware decode of H.264 media, which improves performance with the decoding of unprotected content using the GPU. Also featured is Postscript Vector Printing to improve quality and file size, and an improved graphics stack with 3D support using the XNA API on Windows gains low-level access to the GPU for drawing low-level 3D primitives and vertex shaders, Microsoft's Silverlight team said.

Also featured in Silverlight 5 is a "Trusted Application" model extended to the browser. This means that when the model is enabled via a group policy registry key and an application certificate, users will not need to leave the browser to perform complex tasks, such as multiple window support.

"Silverlight is part of a rich offering of technologies from Microsoft helping developers deliver applications for the Web, desktop, and mobile devices," the Silverlight team said in a blog post. "Download Silverlight 5, a free plug-in less than 7 MB in size that can be installed in less than 10 seconds."

But Microsoft's commitment to Silverlight appears less than solid. Recently, the company said no plug-ins, such as Silverlight, would work with the Metro-style interface planned for the Internet Explorer browser. Metro is new UI and mobile-oriented application mode planned for the Windows 8 OS. Instead, HTML5 will be the technology of choice. And Scott Guthrie, a Microsoft corporate vice president who has been a key advocate for Silverlight, moved over to the Windows Azure cloud platform team several months ago.

Nonetheless, Microsoft marches on with Silverlight.

Analyst Al Hilwa, of IDC, still sees significant potential for Silverlight 5, for the time being. "There is a considerable body of existing apps or websites written in Silverlight, and those apps and their users will benefit from the improvements in the Silverlight runtime, especially the hardware acceleration. Addressing large user populations with HTML5 on desktop browsers is still a challenge because many users will continue to use non-HTML5 browsers for the next two years." Hilwa added, though, that he expects that in five years, fewer websites will be supporting Silverlight and Silveright on the desktop is "strategically challenged."