On November 13, Google announced that it would change the clickable area in AdSense ads. Since Efficient Frontier has over 70 clients that advertise on Google AdSense, I thought I would take a look at how it performed before and after the change.
As might be expected, our data shows decline in CTR of 12% when comparing the week of November 5, 2007 (before the change) to the week of December 3, 2007 (2 full weeks after the the change). While some felt that this might decrease revenue for Google, average CPC actually increased by 13% (from $.30 to $.34) in that same period, while overall spend remained about the same.
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