&#62;Google has a near-monopoly in online video thanks to the ubiquity of Youtube. This means that they are the effective arbiter of codec choices for HTML5 video<p>I don't believe that to be true, and that the true arbiter of web technologies is <i>client</i> support. Look at CSS3, XHTML, Silverlight, or even the "q" HTML4 element which IE didn't support until IE8.<p>The world revolves around what the <i>clients</i> support. This is why Mozilla's decision is so important. You can bet that if tomorrow Microsoft decided to support one codec over another, you can bet that everyone would move over to that single codec, regardless of its technological merits.