If you use Google AdSense to monetise your site, you may know that you are able to place up to three AdSense units on each page of your website. Using more than one ad block may not be effective though, and I will tell you why.
The AdSense pricing structure
The majority of ads on your site appear through keyword matching. An advertiser joins Google, writes their ad copy and chooses the keywords they want to target. They choose an amount they are willing to pay, and then they are off. If your site matches these keywords, ads will appear based on the amount advertisers are willing to pay for each keyword.
Let’s imagine there are fifty advertisers bidding for the keywords associated with your site. The higher these advertisers are bidding, generally the more likely they are to appear on your site. Therefore, if you are running a 468×60 banner, it is more than likely that the two advertisers that are appearing are paying the highest amounts to appear there (and consequently you are being paid the highest amounts for each click).
As you can imagine, as you place more ad units all those advertisers who have bidded lower amounts will start to appear on your site. Whilst you may be getting a few more clicks by adding more ad blocks to your site, you will invariably make less money for each click as you are now allowing advertisers who pay less to have access to your site.
With AdSense, less can be more – consider using other ad networks rather than simply adding more Google ads on your site. Not only is it better to be less financially reliant on one single company, but by using other ads you will be ensuring that those sites advertising on your site through Google are paying you top dollar to do so.