Sources: YouTube has introduced two new internal metrics in the past two years: total time spent on site and the murkier "quality watch time" (Bloomberg)

Bloomberg:
Sources: YouTube has introduced two new internal metrics in the past two years: total time spent on site and the murkier “quality watch time”  —  YouTube is changing the way it measures success on the world's biggest video site following a series of scandals.

from Techmeme http://bit.ly/2X5rer4