sasha, there is a reason why Mozilla doesn't support H.264 - it is because
H.264 is patent-encumbered.
Anyway, if you want WebM support I advise you to get the IceCat browser as it
uses a newer version of Mozilla browser. If you also want H.264 playback
perhaps you should try a WebKit based browser like Midori.
Also, I thought the problem you were having was flash not working on Youtube
via Gnash and Flash Video Replacer and not HTML5 compatibility. Youtube
doesn't deliver all its videos in HTML5 yet and only a small subset of the
videos provided in HTML5 are available in WebM.
