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

However, Yahoo displays a sharp negative correlation (a -71 on a scale of -100 to +100). Pages using Google AdSense appear to rank much lower on average than pages that have no AdSense code. Is this done on purpose? Does Yahoo actually want to penalize pages that use Google's AdSense? We don't know. A statistical analysis can't reveal intent. However, the fact is that pages that use Google AdSense do currently rank lower on Yahoo!

Notes

1. There was no exercise to attempt to isolate different keywords. Keywords came from a random sampling of the queries performed by the author and three associates during the month.
   
   
2. This is merely a correlation study, so it cannot be determined from this study whether the leading search engines purposefully entertain this factor or not. The actual factors used may be far distant from the factor we studied.

Conclusion

Pages which utilize Google AdSense have no significant difference in ranking opposed to pages that do not utilize Google AdSense in the Google organic search engine results.

However, pages that utilize Google AdSense rank much lower in the Yahoo results on average!

Recommendations

If you have a site that is ranked well on Yahoo, and that ranking is important to you, we recommend that you avoid using the Google AdSense program. If your traffic comes from sources other than Yahoo (links, affiliate programs, Google, etc.), then the results of this study shouldn't concern you.

What if you want to use Google AdSense on a site that is ranked well on Yahoo? Well, that could be a good reason for using a content delivery system based on visitor IP. In other words, you could configure your server to mask the short Javascript code supplied by Google AdSense from the Yahoo Slurp spider.

Of course, Yahoo may change their algorithm simply as a result of this study being published. We'll keep you informed in future issues if we notice a change in this ranking factor.

The Geek speaks was written by Jon Ricerca