This is Google’s advertising placement service and it offers an automated revenue streams which assist publishers in creating value of their ads. These ads are usually under-priced, but that is seen as a good option seeing though the ad sales are automated.
The AdSense auction format includes cost per click and CPM. They can also be in many different formats including; graphic, text, videos and GIFs.
The ads are managed and controlled by Google and website owners just have to login to AdSense (it’s free) then copy and paste a provided code to show the ads.