Facebook is testing a new viewability metric for its video ads. This social network added a new option for advertisers to only pay once their video ads have played for at least 10 seconds. Advertisers could still choose between that model and the option to pay once their video ads come into view, or on a cost-per-view basis. Till now, this social network charged advertisers every time a video ad came into view on users feeds. But the on-screen presence of an ad didn’t always count as an active viewership because Facebook rates a view after a minimum 3 seconds of watch time. So if the user pauses an auto-play ad before this time frame, and most likely lose its focus on the ad, brands would still have to pay for the impression.