There's been a lot of discussion lately about whether or not the HTML5 <video> tag is going to replace Flash Player for video distribution on the web. We’ve been excited about the HTML5 effort and <video> tag for quite a while now, and most YouTube videos can now be played via our HTML5 player. This work has shown us that, while the <video> tag is a big step forward for open standards, the Adobe Flash Platform will continue to play a critical role in video distribution.
It's important to understand what a site like YouTube needs from the browser in order to provide a good experience for viewers as well as content creators. We need to do more than just point the browser at a video file like the image tag does - there’s a lot more to it than just retrieving and displaying a video. The <video> tag certainly addresses the basic requirements and is making good progress on meeting others, but the <video> tag does not currently meet all the needs of a site like YouTube:
Conclusione, l HTML5 è ancora troppo acerbo la resa video è una #CIOFECA e Flash dominerà ancora per parecchio (parola di YouTube)