Site publishers who have wondered why certain ads appear where they do in their AdSense blocks can learn about that in Google’s latest AdSense blog post.
AdWords uses a ranking system to order the advertisements appearing throughout Google’s far-flung network of publishers. They have dubbed the system, appropriately enough, AdRank. Simply stated, the higher the AdRank, the higher the ad’s placement online.
Google’s AdSense team discussed how AdRank is calculated:
While bid price (the price advertisers are willing to pay for each click per thousand impressions) is obviously an important factor, we also calculate advertiser Quality Score to make sure the best performing ads will always appear on your site. Quality Score takes into account factors such as an ad’s relevancy and click-through rate (CTR) (i.e. how likely users are to click on a given ad) because a higher CTR sometimes outweighs the benefits of a higher bid price.
As Google explains it, the system is a very good thing for publishers because it places ads in AdSense blocks that can generate the most revenue for a site.
Also, site publishers should not be alarmed when CPM-based ads suddenly appear and occupy some or all of the ad spaces in the block. “It has to produce an effective CPM greater than the sum of the individual text ads,” the blog said.
—
document.write(“Email murdok here.”)
Drag this 
Add to document.write(“Del.icio.us”) | DiggThis | Yahoo My Web
David Utter is a staff writer for murdok covering technology and business.
