Some percent of google advertisment is for free, charity or google propagation. These clicks has no value. It shows in few times with commercial ads, or when there is no commercial ads for your site.
My 5 clicks goes to charity without my permission I am thankful to God that the banks where I have my accounts are not giving my money to charity without asking me
Hahahaha. So funny reply. I am not against it. No problem if some amount of the clicks goes to charity. But it should be clearly mentioned after click like this ($xx.xx for Charity)
It happens with me also sometimes. I have read somewhere that Google has sophisticated algorithm to detect invalid clicks and does not pay for it. I feel the clicks which you are referring to are invalid clicks.
any two reason 1. your ads is show public service adsense (its mean no price) 2. your visitor click and just go (google adsense count $ if visitor click and stay in there web for 30 seconds)
I see this invalid clicks in my account atleast one in a week. I feel like these are the clicks which comes from same IP address or google feels these clicks are just to manipulate the earning. So they de-valued the clicks and make it null.