I wonder, if what Google says is true, then it will always try to show the best paying ads. So, wouldn't it make sense to limit the size, and/or amount of adblocks shown? If Google did show the highest paying ads, then wouldn't a 125x125 block pay better than a leaderboard, in the same place, since it only has one ad? Anyways, this will be an experiment for me, for the next week: replace a 336x250 adblock (shown above the fold, blended) with a 234x60. I'll see if there is any impact on CTR.
After a lot of testing on my sites anyway, I have found that the smaller the ad blocks I have, the less clicks I get. Seems the more I have and the larger they are, the clicks increase. But why wouldnt they ? If you throw a penny on the ground, someone is apt to pass it by, but if you place 5 pennies next to each other, they will soon be grabbed up.......
I was thinking this also the other day. If i have 3 different blocks of ads on my site, only say 3 of the ads are going to be best payers
Let's start with the redundant answer "It depends". Assuming you had two identical pages. Both have one ad, one has the button and one has the med rectangle. The page with the button will likely get a higher CPC. The page with the med rectangle will likely get a higher CTR. The formula you should be concerned with is earnings = page impressions * ads per page * click thru rate * average price per click Let's assume page impression is a constant p. earnings = p * CTR * CPC. The question is, for my page, will the higher CPC justify the lower CTR. Some pages it will, some pages it won't.
thanks randymorin! (I used to go to Karate when I was a kid in Bramalea in the 70s) That is an important point: some things can drive down CTR, when one pursues a higher EPC, which could increase the likelyhood of falling victim to "Smart Pricing". I bet SP could be as easily triggered by low CTR as it could by low conversion rate.