YouTube is starting a major redesign and have made some odd and interesting choices. Amazon recently impressed me by hiding away alot of interface to fit more contest on the screen. YouTube seems headed in a similar direction.
Their new layout definitely looks better then the old one but they have made a choice that does not sit as well with me. In hiding away all those interface elements in dropdown menus they have taken all that new space and put a 300x250 add on the page in place of the 160x600 ad.
Perhaps it’s not glaringly obvious to most people but I can’t look at that page with out imagining a designer told to redo the page so a 300 ad could fit on it. Design that purely motivated by ad placement always make me queasy.