From the end user perspective, sure. From the back end, not really. Silverlight is a proprietary technology controlled by Microsoft, just as Flash is a proprietary technology controlled by Adobe. Apple's stream was using something that they are publishing as a standard with the IETF, just one that no one else has chosen to implement into their browsers. Again from the end user perspective there isn't much difference here since people were locked out. There still isn't any way to guarantee 100% of an audience can watch a streaming video, but at least Apple is trying to make a new standard that works around the problems of the old one (RTSP), instead of making some new proprietary method.

Back to WP7, I just noticed that this is yet another big phone launch without CDMA support in the US. WP7 Verizon phones are a no show, and there is one phone that will be on Sprint sometime in 2011. All the launch phones are aimed at AT&T or T-Mobile. I doubt WP7 will have a huge impact on the Android install base in the US, since most seem to be on Verizon after the big marketing push of "DROID" started last year. if the iPhone couldn't convince diehard Verizon people to switch carriers, I don't see Microsoft having any better luck.