Viacom/MTV announced a web based Digital Asset Management Workflow application completely built in Silverlight 3 (of course using the beta bits for now) and .Net 3.5. This is very cool, not just because it is an early adoption of Silverlight 3, but because :

• It is a great proof point that Silverlight is not just for consumer facing scenarios on the web, but is equally suited for more rigorous applications in broadcast media workflow.
  
• It is one of the first production applications to use the h.264 playback capabilities being enabled in Silverlight 3. MTV creates all their proxies as QuickTime .mov files, with the essence encoded using h.264 compression, either in SD or in HD resolutions. Since QT is essentially a variant of the MP4 container structure, and SL 3 supports parsing MP4 and decoding h.264 natively, we could playback all of MTV’s QT content natively in SL3, without any further transcoding. This was a huge win-win for all involved both from a time and cost perspective.

You can read more about the general press release from Viacom CIO Joe Simon here and about the specific case study here.