Just read this study, late I know but the numbers are impressive

http://digital-media.net.au/article/online-ad-engagement-25-times-higher-than-click-rate/493542.aspx

“Video saw a 30% lift in engagement over non-video banners with dwell time nearly doubling from 37.37 to 71.51 seconds. With more than one in ten users spending over a minute, video banner advertising may be a popular alternative to intrusive pre-roll advertising.”

eyeblaster have done a great job on this report but why are they and other still charging on a cpm basis?
Surely paying for engagement is the way forward?