Blending is what I use on my site. Blending looks like as if the Ads were a part of the site. Users normally react better to this and will click on the Ads because they look like a part of the site. If you blend Ads correctly your Click Though Rate (CRT) should increase, thus increasing revenue. To blend, make the background and borders of your ads the same color as the background of your page where the ad is placed. If your site has a white background and you don’t want to spend a lot of time choosing ad colors. http://wmseo.com/2006/11/10/adsense-blending/