even worse is that there is no cached video while seeking. Even seeking to a "loaded" part of the youtube video results in the reloading the video from that point. Rewinding 10 seconds results in having to reload the video, wtf?
Support for the progress element is still missing from a lot of browsers, so I don't know if it's right to say that the markup is "wrong" for not using it
I like it. Just remember if you use this in production, save $("#progress") in a variable in the ajaxStart function to improve performance (this will call Sizzle one less time usually).
I'm on a fast connection so normally youtube loads instantly anyway, but this new method takes 4-10 seconds.