The amount Google receives per ad click is decreasing as the number of clicks increases, as a bigger portion of total clicks is coming from smartphones, deemed less valuable by advertisers.
In the fourth quarter, clicks on advertiser links next to Google’s search results increased 14% from a year earlier, but the amount Google got paid per click fell 3% from a year earlier.
Revenue per click has been declining for some time and shows no sign of relenting. If this persists, even with ever-increasing click volume, revenue is eventually going to stagnate.