Some of you running Windows Phone may have noticed that the YouTube page that the dedicated application launches was down yesterday and it appears that the reason was Google being hard at work making it recognize Mango’s IE9 and treat it accordingly.

If you run a beta or the RTM version of Windows Phone, once you access YouTube via the application or directly from the browser, you will be greeted by a new, nicer and cleaner look. It seems like YouTube is now reading and recognizing the IE9 user agent and thus employs HTML 5, which is fully supported by Internet Explorer. Those running Windows Phone NoDo or below will not see these changes as the platform doesn’t contain Internet Explorer 9 with HTML 5 support.