I always thought about having the 3rd ad block on my blog or not. That generates 8-9% of total adsense revenue. I think if i kill that then other ad blocks will take away half the clicks it generates and CPC will surely increase by 10-20%. I think overall revenue will remain same if i kill the 3rd block? Do you AGREE?
3rd ad block pays the lowest. most of the times you will make more with 2 ad units than 3 if properly placed. you can experiment for few days to see for yourself