@dda: Well I was about to say...

It's not C9 that I'm mad at. They are doing what they can with what they have. It's WinDiv that is blowing it with excluding a streaming media player in Metro IE 10 that can play flash and SL video full screen before the web has caught up with the capabilities these technologies have. Thankfully C9 made a nice W8 metro app that can render the streams full screen.

...but I just tried webm video on youtube and also this site http://html5video.org/ and they both can play full screen in Metro IE 10. Yes there are artifacts probably because it's scaled but at least it provides some something that's easier to watch on a tablet without pressing your face to the screen. So how is this done? It's the video player (i.e. http://www.kaltura.org/project/HTML5_Video_Media_JavaScript_Library). Looks like the ball is back in C9's court. The IE team could make it better by providing native support but they'd make a lot more people who will be buying W8 tablets this fall happier if they at least provided a player like the one I've sited. C9 could implement this kind of player today and not wait for the IE team.