|Kevin Lee from ClickZ said: |
...the Google AdWords system displays ads in the order of the effective CPM of the ad rather than that of the maximum specified CPCs. This means the ads with the highest effective CPM are placed in heaviest rotation, maximizing revenue. For example, an ad with a 4 percent CTR and a $0.25 CPC ($10 CPM) will rotate into higher positions than an ad with a $0.35 CPC and a 2 percent CTR ($7 CPM). The higher CPC does not get better placement.