Someone suggested using Chitika as an alternative to Ad Sense, so I gave them a test run yesterday. It was only a 1-day test so I can't say whether it would have improved with time, but this was the longest I could afford to give.
On higher resolution screens, I have two 300x250 banners on the right column... one above the fold, followed by some content, followed by the second banner that's either on the fold or below the fold, depending on their screen.
With Adsense, the BTF (below the fold) banner location has about the same number of impressions as the ATF (above the fold) location. It is my lowest performing banner based on Impression RPM, so it's the one I could afford to test.
It is also notable that I have Adsense Ad Balance set to 100/62.
So I left the ATF banner with Adsense, and the BTF banner I moved to Chitika.
Yesterday, the ATF banner using Adsense had 24,708 impressions. Based on the ad balance, I'm guessing that there were about 40,000 requests, and 16,000 of them were passed.
In comparison, the BTF banner had 5,810 impressions. Chitika also said that 4,121 were blocked (I'm not sure if that means the end user has an ad blocker, or if they blocked the ad request based on page content), and 38,027 had "no bid". That adds up to 48,000 ad requests, though, so I'm not sure if the Adsense math is off or if I'm counting it up incorrectly.
Then, comparing the revenue generated through the BTF banner on Chitika as compared to the same location the previous day with Adsense, Chitika raised 0.44% as much revenue.
Meaning, if Adsense was $1, then Chitika was $0.0044. So drastically less.