[johnmmix]

I've not done any exhaustive testing, but beware that some YouTube videos won't play in Mobile Safari, even though they play fine on the standalone iPad YT app. Instead you get the "You need to upgrade your Adobe Flash Player to watch this video" warning.

e.g. "New order - Perfect kiss (10 minutes version)", http://www.youtube.com/watch?v=--pSWLEVGhY

[macrael]

That video appears to play just fine without flash if you change your user agent to iPad.

[johnmmix]

Sorry, wrong link - the URL used for the iframe embed version (which I guess is what you'd use to include the video on a regular webpage, rather than the link I previously posted) is http://www.youtube.com/embed/--pSWLEVGhY

On regular Safari pretending to be an iPad, this plays the video in Flash player; on a real iPad it comes up with the "install Flash" message.

If you view source on that embed link, near the bottom you'll find a JavaScript array called FORMAT_MAP, which is empty. On a video which is available in HTML5 formats, this would have multiple members, containing the URLs etc for the video in different formats/quality.