In an interview Bob Muglia, Microsoft server and tools president, says the company's "strategy has shifted" when it comes to Silverlight.
He describes HTML5 as "...the only true cross platform solution for everything, including iOS."
This confirms Microsoft is pushing for HTML5-- Internet Explorer 9 carries many HTML5 features, Bing will carry new HTML5 powered features, and H.264-encoded HTML5 video delivers live video on its 360 game console.
Silverlight will remain Microsoft's Windows Phone development platform. Muglia says Sliverlight has "sweet spots" in media and line-of-business applications.