Microsoft Corp. this week will reveal new technology to deliver rich media applications on the Web, part of a broader strategy to go head to head with Web and design tools powerhouse Adobe Systems Inc.

As described by Forest Key, a director of product management for Microsoft's Server and Tools Division, Silverlight is a browser plug-in that allows Web content providers to offer rich video and interactive media experience from directly within Web sites. The technology, which leverages Vista's new graphics framework Windows Presentation Foundation (WPF), will debut at the National Association of Broadcasters (NAB) conference, being held this week in Las Vegas.

Microsoft also will unveil Web content providers who have signed up to use the technology once it is available, including Akamai Technologies, Brightcove Inc., Eyeblaster Inc., Major League Baseball and Netflix Inc.

Key said Microsoft is targeting three core audiences with Silverlight, formerly code-named WPF/E: content providers that want to distribute video and rich media over the Web; designers and developers that are building rich interactive applications; and end users that want the best possible experience when viewing Web-based media.

Silverlight is compatible with a range of browsers, including Internet Explorer (IE), Safari and Firefox. As demonstrated by Key, the technology delivers a similar user experience on both IE 7 running on Windows Vista and Firefox running on an Apple Macintosh computer. In fact, a big benefit of the technology for end users is that they will not have to download different video player technology to view online media based on what OS they are running, Key said.

Microsoft is highlighting the video-delivery capabilities of Silverlight at NAB, but the company plans to show how companies can use Silverlight in a similar way to Adobe's Flash to deliver Web-based applications that use animation and other rich media, Key said.

Microsoft also plans to optimize other components of its software platform to add value to Silverlight. For example, the forthcoming Windows Server, code-named Longhorn, will include as a plug-in the IIS7 Media Pack, which adds new features to enhance and reduce the cost of delivering rich media over the Web.

Microsoft's Expression toolset to build rich Internet applications -- which Microsoft is pitting as an alternative to Adobe's recently released Creative Suite 3 -- also is key to Silverlight because designers will use it to create application to be delivered through the technology. Expression should be generally available in June.

Keith Cutcliffe, IT developer and analyst for ProAssurance Corp. in Birmingham, Alabama, is skeptical that Microsoft will ever gain the faithful user base Adobe has. However, he said that enterprise customers that have developed Flash applications to run on Microsoft-based Web infrastructure eventually may use Silverlight and Expression instead because of the underlying back-end platform ties.

Scott Stanfield, CEO of application development firm Vertigo Software, seems supportive of that sentiment. He said Silverlight fills a major gap in Microsoft's strategy to provide a mechanism to deliver and build applications that provide the stability of desktop applications with the user experience of media-rich Web applications.

"Previously Flash was the only answer," he said. "Now Silverlight becomes a viable alternative."

Microsoft will deliver a beta of Silverlight at its MIX 2007 conference at the end of April, and will announce plans for general availability at that time, Key said.