1. People might be clicking on Public Service ads = no revenue for you. 2. People are just clicking low paying ads. You can get rid of those. 3. Might be getting invalid clicks, such as those from 3rd world countries, etc.
what you mean by third world country? I am getting clicks from UAE, Singapore, malaysia 250 cliks and $8 Is it these countries are third world?
all the ads i see i would say are low paying. you got ebay,wallpaper,anime,ringtones,and emoticons ads.
Of course they are, but the chance of someone from Africa buying your product is not that high US traffics pays better.
I suggest putting different type of keywords on your site. Better ads would bring it up like others said.