I'm sitting in on SilverlightDevCamSF today and it's been interesting. Keep in mind I'm here as an Adobe employee so all of the standard biases apply. This is going to sound mean, but there are more people here than I thought there would be and only a couple of them are people I recognize from the Flash community. Silverlight is definitely appealing to a new group of people, which is great for RIAs.
I think most of the people here are beginners who haven't played with Silverlight much but are interested. There were a couple of things that were interesting from the Silverlight 101 session by Sean Brian Ellis. One is that Microsoft's goal is to get 200 million downloads of Silverlight by June 2008. That might correspond with a release date for 1.1 but they didn't say that.
Another interesting tidbit was that Microsoft has talked about doing a binary format for XAML, their markup language. As the XAML gets more and more complicated, Sean said that they might look into a binary format for performance reasons. The plain-textedness of XAML has been one of the differentiators between binary-based Flash, so the option to do either binary XAML or plain text XAML would be interesting.
There was a session on Silverlight versus Flash which mostly consisted of people clearing up miscommunications. Right now Abdel Remani is doing an atrocious session comparing JavaFX, Flash, Flex, and Silverlight. There's just so much confusion still around RIAs that coming to things like this make my blood pressure rise.
I won't be able to stay for the whole thing, but it's been a valuable event. There are a lot of people asking good questions about both Silverlight and Flash as well as rich internet applications in general. I think we're getting the message across that design and experience are things that developers should focus on and think about.