There is a rather significant problem with the example above. When you use multiple ad units on one page, Google will typically serve up the highest paying ads first and the lowest paying ads later.
In the example above our obvoius ad, which was inserted not to create a lot of clickthroughs but rather to set a "tone" for ad design throughout the page, appears first in our source code. This means that this "diversion ad" will hold the best paying clicks, but will probably rarely be clicked on.
It is not always true that ads that appear first on your page will earn you the most money. When optimizing your Adsense ads, try setting up channel tracking on each of your ads to see which ad spot gets the most clicks and which ad spot receives the most money per click. Once you have determined this, you should rework your code to try and get the ad with the most clicks to appear in the spot of the ad that receives the most money per click.
