"In the US, Google received around $35 bln for the digital ads in 2017, while Facebook captured more than ‘one in five’ US digital ad dollars with a total revenue of more than $17 bln. But, according to BitClave, businesses have little guarantee the traffic they generate on their promotions is genuine." ...
https://cointelegraph.com/news/how-to-get-paid-for-your-web-search-a-startup-to-give-data-control-back-to-users