this should probably be in adsense forum, but it's okay...
Google cares about it's advertisers(or at least about keeping them around because that's where they get the money)
The publishers they don't care as much about...
What happens is person comes to your site, they click on ads, but they are untargeted traffic. They click really fast and then they leave.
Or they click on the little arrow to see more ads then they leave...
The advertisers would get pi$$ed if they had to pay per click if people click on and then off, especially if it's a quick accidental click. So google says "don't worry about it we got your back" or something. So google says "okay, you the publisher get half a cent, while the advertiser pays Google .05 cents because click was untargeted traffic and it "bounced" off of the ad almost the instant it clicked.
If you want to increase what you make per click, you need to forget about social traffic for adsense, and concentrate ads on focused pages. Also don't put ads up until after awhile so google can index your site, and figure out what kind of ads to display...
refer to this post
http://www.blackhatworld.com/blackh...rove-earnings-without-increasing-traffic.html
for some ideas
I'm using blogger, I didn't have to create any ad units. I'm still not recieving money from any clicks and I do have allow any other site. All my other sites are working tough.