Are you wondering about why the CPC you are receiving for AdSense is lower, even if your content is being served with high paying ads. There has been lot of talk and discussion about getting high paying ads. One most important point in this, one should know that Google serves top paying ads in order. So first ad on your page will always be carrying max CPC. Now if this ad is being shown on top header where users are least likely to click on it, you are wasting a chance to get max CPC. So if you are showing ads all over content page without regard to Google heat map, you may be loosing lot of money just due to poor ad placement. Key point is to serve less ads which will have high chances of getting clicked and highest possible CPC. Showing less ads also has a side benefit of increasing the competition among advertisers for top spots. If your page is showing 12 ads, those many advertisers will get chance to get their ads displayed at lower cost, but you have only 4 ad spots they have compete to get their ads on your pages. Also, with less ads your site visitors would be less annoyed by the ads splattered over content pages.