If you notice in the HTML5 beta on YouTube, they will only choose to play the video with HTML5 over Flash if the video doesn't need to contain ads (which is almost no videos anymore).
This makes me wonder, how are they going to go about sneaking ads and commercials into videos after the complete migration to HTML5 video? This sounds like it will be counterproductive for everyone. YouTube will be reluctant to completely switch to HTML5 because they can't slap ads in your face. And because they are *the* video website on the internet, they basically control how videos on the web are used, everyone else will follow suit.
This makes me actually hope that there is a way to stick ads in html5 videos, sadly. Otherwise, the migration to html5 video might take even longer.
I don't have much actual experience with the <video> element or the DOM behind it. Is there a way to actually stick ads at the beginning, middle, or end of a video?