NBC just published their first press release about the usage of nbcolympics.com.
Some quite impressive numbers:
All in all to date is a great success and (may I say) a clear indication that Silvelight is emerging as a sound technology to deliver high quality media over the Internet.
Unfortunately (due to international broadcasting rights regulations), the video content is not available outside of the US, but I hope the NBC example will pave the way for similar models in the future.