Comment Branding over functionality... (Score 4, Informative) 369
It seems that both Youtube and Vimeo have both chosen to use their own custom controls, and disable the default controls native to the user's browser.
That wouldn't be such a big deal, except for the fact that full screen mode can currently only be entered using those default controls (making full screen mode available via a scripting api is considered a security risk, and thus discouraged by the HTML5 spec). So they're sacrificing that functionality at the alter of branding.