Very interesting read there burcot...only problem is my users using that screen resolution is getting smaller and smaller. Now about 15% with 80 % being larger.
Why that adsense rep wanted more ads is beyond me. By adding a vertical leader board(right side) or 160 x 600 did absolutely nothing to my earnings when instituted about 10 weeks ago. I may just go back to div in content only again that would raise my content to ads above the fold to about 70-30%
I wonder if images have an effect. Would that be considered content? I have at least one image above the fold on most pages that basically establishes upon landing on the page "this is what the page is about" and directly relates to the title and H1 tag.