go to m.youtube.com
scroll to bottom of page.
click "optimize"
click "start optimization"
test 1/7: click "yes" when you see the tiny grey heart
test 2/7: click "yes" when you see the puppy
test 3/7: click "no" when the flash lite video fails
test 4/7: click "click here" when pressing "5" key does squat
test 5/7: there is no test 5 for some reason - skip to test 6/7
test 6/7: click "YES" - the mp4 test video WILL FAIL BUT CLICK "YES" ANYWAY
test 7/7: click "no" - h.263 does not work
Click HERE or email yourself the link if "Optimize" does not appear at the bottom of your page.
Thanks! Worked for me as well, though this is the first time trying Youtube even before this solution. Is it just me or is the bar that allows you to stop, play, skip constantly flickering while the video is playing?