From this page (http://blogs.msdn.com/b/ie/archive/2011/03/16/html5-video-update-webm-for-ie9.aspx http://blogs.msdn.com/b/ie/archive/2011/03/16/html5-video-up.

From this page (http://blogs.msdn.com/b/ie/archive/2011/03/16/html5-video-update-webm-for-ie9.aspx http://blogs.msdn.com/b/ie/archive/2011/03/16/html5-video-up...) they say, "IE9 supports HTML5 video using WebM for Windows customers who install third-party WebM support." From (http://blog.webmproject.org/2011/03/introducing-webm-in-internet-explorer-9.html http://blog.webmproject.org/2011/03/introducing-webm-in-inte...) the WebM team says, "Microsoft collaborated closely with us to make the components fully compatible with HTML5 in IE9, so features such as the <video> tag and its canPlayType method are fully enabled for WebM. Our thanks go out to the Microsoft engineers who provided technical assistance and hosted our team in Redmond last month." Does this sound like a company that opposes it?