When does Google Pay?

Im not quite sure what you mean. Do you mean your only getting paid for half the people clicking on your adsense ads?

Yes, that is what I mean. I show clicks but no payment.
I don't have any payment on my adsense search for instance, but I have clicks.

On some days, I have clicks but no payment on my adsense for content.

google has a system in which pays only for real click, some click can be fraud and thats why you are not paid.

I wonder how they determine that. I, personally, have not even visited most of these sites for awhile. Oh well.

I ask them once, they send me once an email and told me that I have some invalid clicks on my website, any way I just reply them back and told them to describe me thier system, how is working etc, and guess what they told me, We are sorry but we couldnt review this to you. So dont bother to ask google about how their sistem works because they wont tell you.

In my opinion, Google is just a rip off. We used to use the for advertising. We installed a third party tracking system. Our tracking system is giving us less clicks that what Google is showing. So our advertising manager decided to just cancel them. I heard there is a lawsuit on them.