Twitter on Tuesday unveiled something new in its timeline: autoplay videos. And unless a promoted video is 100 percent viewable (not half-off-screen or scrolled by) and has been watched for at least 3 seconds, Twitter will not charge advertisers for the view.

Twitter’s senior product manager, David Regan, discussed this in a blog post:

As with all of our ad products, we’ve made sure that Promoted Videos on Twitter will continue to deliver high impact, high engagement and meaningful views for our advertising partners. To that end, we’re approaching how we measure, report and charge for video views with complete transparency. We’re delivering on a new standard for how brands will be charged for a video view. Starting today we’ll only consider a view on Twitter chargeable when a video is 100% in-view on the user’s device, and has been watched for at least 3 seconds. We’re putting this standard of 100% viewability in place because we think it’s simply the right thing to do. If a video is not 100% in-view, we don’t think an advertiser should be charged.

Now, when a Twitter user scrolls through their timeline and sees a GIF, Vine or native Twitter video, that content will start to play automatically. Twitter has been playing with autoplay features for a while, and Facebook had a dramatic test and rollout of the feature as well. With Facebook, many users feared the ruination of their News Feed, but pushback has been minimal so far.

Just like with Facebook, there will be no sound in the autoplay video until the user taps on the post or turns their mobile device sideways for landscape viewing.

Users can choose to limit or turn off autoplay video (for data purposes) through their settings.

Baljeet Singh, Twitter’s product director of media, television and video, blogged about the autoplay video feature:

It used to be that watching a video on Twitter required several taps. So when something was unfolding in real time, be it an NBA finals game, your favorite TV show or breaking news, that extra effort meant you could miss something that you care about. Over the past year we’ve made several changes to improve how you share, discover and watch videos, such as reducing the number of taps it takes to play a video, introducing a native mobile camera and bringing videos and Vines front and center in your timeline. Today, it’s become even easier to enjoy video on Twitter. Now native videos, Vines and GIFs will begin to play back automatically. So you can keep up with the action without missing a Tweet and get a better sense of what’s been shared instantly.

Readers: How do you feel about autoplay video on Twitter?