People have been speculating about when Facebook would start running auto-play video ads in its news feed for a year or more, but yesterday the social network unveiled its plans, after noting a 10% rises in people watching, liking, sharing and commenting on non-ad videos that automatically played. “This week, we’re starting to test this richer storytelling format for advertisers,” announced Facebook yesterday, revealing a partnership with Summit Entertainment and Mindshare to make the first campaign a series of videos for upcoming film Divergent. The videos will automatically play without sound when some users scroll to them in the news feed, but they’ll require a tap or click to trigger the sound. Meanwhile, the videos will only be downloaded in advance over a Wi-Fi network for mobile Facebook users, to avoid hefty data bills. “This is an initial, limited test. We will let you know if/when the product becomes more widely available,” Facebook told marketers on its blog. “We do not disclose pricing. The goal for this test feature is to be a premium advertising format on Facebook, intended to reach a large audience at specific times.” Estimates earlier this year suggested anywhere between $1m to $2.5m per day for the slots.