This is interesting. Google still hasn't completely converted over to HTML5 video for YouTube. You've been able to opt in to the trial for years now ( http://www.youtube.com/html5 ). But it seems that more than half the videos I watch are still using the crappy old Flash player. Content wise, YouTube has way more content to convert to be able to take advantage of HTML5. I wonder if Netflix is having to convert video…
They won't. They're using H.264 video, which all major browsers can play in HTML5 tags now. Not so sure how they'd handle stuff like multiple audio tracks though - as far as I know they're bit of an issue now even if muxed with the video, and if you don't want to load extra audio tracks then you're pretty much out of luck since there's no decent way to play video and audio separately in sync with HTML5 at the moment (a combination of and isn't exactly that reliable for this).