When I want to see if a page has valid XHTML, I go to google and type "validation" - then click on the W3 link (also at http://validator.w3.org/). I've noticed that lately, this youtube video and W3 have been battling for the top spot. It seems that every few days, they switch back and forth between the #1 and #2 positions... Kind of interesting - did anyone else notice that? How can a youtube video possibly outrank the W3?