I notice the Google heatmaps are never updated. I see many forums using a different model than they suggest. Any thoughts on how valid they are? http://www.google.com/images/adsense/en_us/support/forum_en.jpg
Well, google rarely updates their optimization tips. To me, the best ad placement for your site is to found out through experimentation. Try many placements and conclude on one that fetching more earnings.
I put an ad on the top left of one of my sites, which is where the heatmap suggets. While it earns about $30 a month and this is nice, it is less than the leaderboard makes on that site by a HUGE margin, which is right where people aren't supposed to click ...