The problem with time on site is that it can also mean "time spent looking for what I want to see but can't 'cause I can't find it." For a commerce site or a sa

The problem with time on site is that it can also mean "time spent looking for what I want to see but can't 'cause I can't find it." For a commerce site or a saas site this is terrible user experience. For FB, it's terrible user experience too but a great metric to show advertisements. What a bad incentive they have.