yeah, of course it is, but same is the case with many of other Microsoft related websites.
In fact, I will try to put up a list.
This is the post "Delivering fast boot times in Windows 8" in windows blog
http://blogs.msdn.com/b/b8/archive/2011/09/08/delivering-fas...
You can see that the video(in Silverlight) at bottom loads without you having to click on it. It eats up bandwidth.This is the latest Microsoft webpage that I remember in which the video gets loaded automatically.
It doesn't load automatically for me.
Win 7 using Chrome 13
It's a plain HTML5 <video> tag with nothing saying to autostart. It'll work however your browser is configured to handle video tags. It doesn't autostart in any of mine.