In order to maximize their revenue Google displays the relevant ads that have the highest cost per click first. If you have only one ad unit on a page you get the cream of the crop. To fill additional ad units with unique ads you get down to the lower tiers. The first ad in the first ad unit may be worth a dollar a click while the last ad in the last ad unit may be worth a nickel. By using less ad units per page you are more likely to display high value ads.

With the new ad set-up I can display just one Google ad unit on each page. The theme that I use, and probably most WordPress themes, presents some information on the front page that they do not present on post pages. On post pages I have a large rectangle Google ad unit between the post title and post content. There was also a wide tower unit in the sidebar. By positioning the tower unit in the section that is only displayed on the front page I can now display only one Google ad unit per page. I do not use the large rectangle on the front page.

I replaced the Google tower unit with another networks tower unit, and moved the Google unit down to just before the meta section. This falls between my category links and my external links sections. Then after the external links is the Google tower unit on the home page. On post pages I have my large rectangle and the tower unit from my second network, but the Google tower unit does not display because it is located within the sidebar content that only shows on the home page. My visitors will see two ad units on each page, but only one Google ad unit on any page.

I went with NetKlix as my second ad network partner. They were the first that I found when I began my search. Perhaps I should have researched a bit further, but there was a recommendation from a blogger and the program seems to fit with the site, so I filled out the application and now have NetKlix ads on my most active site. I will probably put some of their units on a couple of other sites soon, and then I will see how they perform.

The possible down side that I see from this is that now there are two payment thresholds to meet. If the Google ads are really of more value than it may not make a difference as far as payment frequency. On the post pages the Google ad has the prime territory. On the home page the NetKlix unit is above the Google unit, but if a user scrolls the entries they will be exposed to both. Most search traffic is sent directly to a post page, so this will be an interesting experiment.

Have you tried other ad networks on your sites? What have the results been?