Youtube html5 beta enabled but still uses flash

HTML5 on YouTube doesn't support videos with ads, captions, or annotations and it requires a browser that supports both the video tag and h.264 encoded video (currently that means Chrome, Safari, and ChromeFrame on Internet Explorer).

What version of Safari do you have? (Must be 4 or higher.)

Did you enable it here: http://www.youtube.com/html5

 

It took a couple of hours for the site to change for me, and the interface dies look quite similar to the Flash version. You can tell the difference by right-clicking on the video; if the popup menu doesn't mentionFlash, you're using HTML 5.

I switched back after a couple of hours. The HD videos were quite laggy even on my 2.66 GHz Core 2 Duo iMac.

 

So that's why when i view youtube its still in flash. I have yet to enable html5.