Top Ad Inside a Google AdSense Unit Is The Highest Paying Ad
July 3, 2007 by Gaman
Rustrybrick of Search Engine Roundtable points out to a thread at WebmasterWorld forum that confirms what many people have suspected for a long time.
A member asks if the AdSense ad that appears first in an ad unit is the highest paying one in term of earning per click (EPC).
Someone from AdSense confirms that in a general ad auction, their system will target the highest paying ads to the ad unit and shows them first, working down through the auction results to fill in the rest of you ad units in order.
As an example, someone who clicks the first ad below will earn me more money than the next one immediately below it and so on. However, keep in mind that for site-targeted ads, i.e. ads that appear on my site because advertisers specifically target my site, the auction would be on a CPM basis.
So those paying the highest CPM will appear first in the ad unit.