I think advertising revenue should be preserved until Q3 2012, when Microsoft should go on a vast media blitz advertising Windows 8 and Windows Phone 8 (or 7.5 if we're still on that then). Either way, being able to push the Metro UI on both on computers and tablets and phones all at once could be effective. And I think a consolidated advertising push would be the best way to handle it, not a little WP 7.5 advertisement in Q1 2012 and a little Win8 advertising in Q3.
When that push comes, ads in theaters should be a part of it. So should TV ads, product placement in TV shows, and other forms of advertising though.