YouTube Now Testing HTML5 as Alternative to Flash
youtube-global.blogspot.com/2010/01/introducing-youtube-html5-supported.html
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Sign up for the beta on this page, and boom, you get videos using H.264 and the HTML5 video tag instead of Flash. Working great for me. Note, though, that it only applies to videos on youtube.com itself — YouTube videos embedded in web pages on other sites still use Flash.
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