Instead of cost per pageview, or cost per click, it's cost per amount of time the ad appears:
http://adage.com/article/media/digital-advertising-ready-ditch-click/295143/
The idea is that if you can make time the premium, then you can charge more.
http://adage.com/article/media/digital-advertising-ready-ditch-click/295143/
The idea is that if you can make time the premium, then you can charge more.