September 2018 Facebook introduced ThruPlay ad optimization for video views campaigns. Facebook counts a ThruPlay when your video ad is watched to completion, or for at least 15 seconds (if your video is longer than 15 seconds). Starting July 31st ThruPlay will be the default optimization for all video views campaigns, replacing the familiar 10-second video views optimization. If you have existing10-second video views optimization campaigns they will be paused and you will need to adjust those campaigns to use the ThruPlay optimization.