I've tested with different Adsense ad formats and have noticed that the skyscraper ads are especially poor performers! I think it annoys people to see ad on top of ad on top of ad! I am currently testing a skyscraper on my site http://MakeBigMoney-Fatherspirit.blogspot.com/ and it is doing very badly! Overkill mode! Banners don't cut it either! The rectangular single ads positioned high up on your page and fairly central seem to be the best performers. Have the colours of the ad blend in with your website but be sure to alter the scheme every now and again for a fresh market! A lot of people don't seem to do this but use a different color for ad heading, ad body and the URL, this is the subtle stand-out feature rather than all garish colors. The background is best matched to your page color. Good Luck! Dave.