With the rollout of a new website, Micrososft shares more of the vision.
"Silverlight is a cross-browser, cross-platform plug-in for delivering the next generation of media experiences and rich interactive applications (RIAs) for the Web."
http://www.microsoft.com/silverlight/
I look forward to MIX07 as more details are announced:
from Soma's blog: "Silverlight announcement at NAB is only part of the story, the rest will be unveiled at MIX including details about how Silverlight is a core component of Microsoft’s broader .NET platform. Keep your eyes on Mix07 as part of Ray Ozzie’s and Scott Guthrie’s keynote – be sure to check it out. "