As you may already know, Google offers site owners the opportunity to display Google AdWords for a piece of the pay-per-click revenue generated whenever a site visitor clicks on an AdWords ad. Recently, many SEOs have theorized that Google gives ranking preferences to participating AdSense sites within Google's organic search results. So, we decided to test out that theory as well as take a look at how Yahoo ranks sites that display the competing Google AdWords. The results were surprising!

As usual, we decided that a simple statistical analysis would easily answer this question. We gathered the results of the queries that we naturally performed last month using both Yahoo and Google and analyzed them.

We had to visit each page and check the HTML source code to see if there was a reference to googlesyndication.com – the domain Google uses to serve all Google AdSense ads. We counted the number of pages that utilized googlesyndication.com for the first 8 rankings. The results for both Yahoo and Google were kept separate so that we could discover any differences between the two leading search engines for this factor.

The resulting graphs show the number of pages utilizing Google AdSense for each of the first eight rankings.

Here is the graph for both Google and Yahoo:

Google Results

The result is very conclusive and very surprising. Google shows no trend at all. When we normalized the correlation for Google, we came up with a -21 on a scale of -100 to +100. Anything between -35 and +35 is generally considered insignificant. It appears that Google's representatives are telling the truth when they claim that AdSense is not a factor in determining their organic rankings.

Yahoo Results

Howeve...