This article was recently posted on ZDNet, detailing Microsoft’s diminished mentioning of Silverlight in their keynote. From the article, it sounds like Microsoft is positioning Silverlight to become their mobile development platform, with HTML5 becoming their main cross-platform focus.
This change in focus correlates with the increased popularity of Apple’s iOS platform. It makes some sense that Microsoft would want to avoid have a proprietary development platform on iOS, as Apple has been pretty hostile toward’s Adobe’s Flash platform. I don’t see the longtime rival acting any differently towards Microsoft. In this instance, HTML5 makes more sense when attempting to reach the populous iOS market.