Well the average price per Facebook ad rose 43% in Q4 2017 (and only 3% in Q4 2016): https://www.marketwatch.com/story/facebook-earnings-stock-touches-record-af

Well the average price per Facebook ad rose 43% in Q4 2017 (and only 3% in Q4 2016): https://www.marketwatch.com/story/facebook-earnings-stock-touches-record-after-massive-ad-price-increase-2018-01-31 https://www.marketwatch.com/story/facebook-earnings-stock-to... That increase more than offsets the decline in the amount of time users spent on Facebook. So it looks like the value of advertising has improved.