Cool idea. Why on earth it's presented as an image, and a huge one, I'm not sure I'll ever understand.
Looks like an export from Balsamiq.
Check out the very bottom of the image.
Because as you think about creating your video (which is almost necessarily many times bigger than any image in file size) you're supposed to think: "what about all the spoken word and textual content of this video file, why can't I access it like any other online text?" in the same way you do today when confronted with large amounts of text in an image, but strangely people don't think that today about video because video accessibility isn't part of the standard web practice (yet).
Yeah, and to kill Flash HTML5 really need to reinvent DHTML+TIME to replace the ancient setTimeout() function.
HTML5 is heading towards a hyper-bloated multimedia platform.