In a blog post, Bob Muglia said the interview where he spoke about Silverlight at PDC10 was "accurately reported." He reconfirmed that Microsoft's working on the next release of Silverlight (cross-platform) and that Silverlight will continue to be important to developers in Windows Phone and Windows markets.
Muglia restated that Silverlight is a good development platform for media and enterprise apps. "Silverlight provides a rich UI framework that enables smooth animations and lends itself very well to touch input and embedded devices," he noted (meaning, in this case Windows Phones and embedded devices, not slates/tablets).
Muglia also said, that Microsoft no longer considers Silverlight as the best way to install a single runtime on all devices. For that, Microsoft is planning to rely on HTML.
From today's post:
[…]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. At Microsoft, we're committed to building world's best implementation of HTML 5 for devices running Windows, and at PDC10, we showed the great progress we're making on this with IE 9.[…]
The purpose of Silverlight has never been to replace HTML, but rather to do the things that HTML (and other technologies) can't, and to do so in a way that's easy for developers to use.