Microsoft CEO Steve Ballmer talks to PDC 2010 attendees about HTML5.

If one thing was made clear at Microsoft's Professional Developers Conference last week, it's that the software giant wants in on some of the HTML5 mojo competitors have been trumpeting over the last year or so. What wasn't made clear, however, was the future of Silverlight--Microsoft's media runtime that competes with HTML5 in a number of areas.

That much was presented to developers in the company's keynote, which encompassed updates to its virtualization and cloud computing platform, all the way to new phone apps and a platform preview of the company's update of the Internet Explorer browser. While talking about these last two items, Microsoft's CEO Steve Ballmer paid special attention to HTML5, even bringing up IE9 chief Dean Hachamovitch to demonstrate how IE9 could handle HTML5 much better than browsers from competitors like Mozilla and Google.

The big problem was what wasn't mentioned: Silverlight. Short of Ballmer making note of Silverlight being used to stream the keynote, and the rest of the event sessions to remote users, there was no talk of where the platform was headed. This was later emphasized in an interview with ZDNet, where Microsoft's president of server and tools, Bob Muglia, said of Silverlight that "our strategy has shifted," and noted that major release cycles for the runtime had slowed.

Largely in response to that article, and some of the backlash from developers over the weekend, Muglia has authored a guest post on Microsoft's Silverlight Team Blog entitled "PDC and Silverlight," that apologizes for any confusion, and reaffirms the company's efforts on the next version of Silverlight.

Muglia also noted that by saying the company's strategy had shifted, it wasn't necessarily a bad thing. "This isn't a negative statement, but rather, it's a comment on how the industry has changed and how we're adapting our Silverlight strategy to take advantage of that," he said.

Part of the reason for that change, Muglia explained, is that form factors for devices have grown at quite a clip.

"When we started Silverlight, the number of unique/different Internet-connected devices in the world was relatively small, and our goal was to provide the most consistent, richest experience across those devices," Muglia said. "But the world has changed. As a result, getting a single runtime implementation installed on every potential device is practically impossible. We think HTML will provide the broadest, cross-platform reach across all these devices."

In early September, Microsoft published a piece on the same blog called "The future of Silverlight," which detailed how the company's runtime would co-exist, and in many cases--overtake what HTML was used for in Web activities. The piece also noted that Silverlight is not just limited to being used in the browser, as can be seen in the runtime's spread to other Microsoft devices like Windows Phone 7.

The next version of Silverlight is largely expected to be unveiled at next year's Mix conference in Las Vegas, where previous versions--including the first one, were unveiled.