Here's the results of an experiment on how the number of adsense on a page influences site revenue: http://www.highrevenue.com/adsense/testing-adsense-ad-placement-quantity It's a battle between CTR and eCPM. check out the details. What have your experiences been?
This is an interesting article. I have to say that my experiences don't mirror this person's experiences. Having said that, I have always advocated testing, testing, testing! That is the only way to succeed with this. Without testing and tracking, you have NOTHING! This test you found will only be conclusive after at least a month of data. I would like to point out that since he is making more money, prolonging the test obviously is not a bad thing TomG.
I have a site I have been testing with on 400 pages they all have the same size ads on them but 2 different stlyes they are text only ads on 200 pages the other 200 pages are text and image ads, I will be testing another month like this. all same size ads 120x600 vertical -728x90-250x350. Plus a link unit on all pages of the site 120x600 image and text 57 clicks at $9.57 120x600 text only 11 clicks at $1.29 250x350 image and text 49 click at 5.22 250x350 text only 7 click at $1.57 728x90 text and image 85 click at $ 9.52 728x90 text only 9 clicks $1.22 5 unit link at 89 clicks at $9.41 Each of these ads have there each channel this is why you got to experiment with each now these clicks are from last payment of march so these are april may and this month. In my case it looks like the text and image ads work better than only text ads in which some text ads only do pay a little more but not in all ads. but keep in mind this site has over 900 pages the rest of the site is different ads service in order not to get smart priced.
It will probably be extended not just to the end of this month but to next month as well. After that, maybe we'll look into changing the LOCATION of the advertising on the page to see if it affects income.
I also use three ad unit but my 250*350 performance is much better then any other ad unit..Yesterday only i got 53 clicks on 250*350 ad unit and earned $12.99. Other unit is little low then this.