Nestled in your customer's Facebook newsfeed, between engagement photos of an old college crush and a lengthy post from Aunt Vicky about her blessed life, sits your latest promo video, and it's being completely ignored.

At this week's Salesforce Connections conference in New York, Facebook's CMO Gary Briggs pointed out a trend of brands adding text to videos to capitalize on the site's auto-play function. If you haven't picked up on this trick--you're making a huge mistake if you're actually trying to reach new customers through the world's most popular social network

With Facebook's auto-play function--videos begin on mute when a user scrolls past--marketers can send a message without waiting for the user to click. But the opportunity is wasted if you don't make a change in the way you're creating videos. Testing for this feature started in 2013, but some brands still haven't caught on and are losing viewers because they're not creating videos with the assumption that the first few seconds will play without sound.

A snappy opening line doesn't do the trick anymore, and as you probably know, you only have a few seconds to capture viewers' attention before they click away. But with the autoplay feature, you have the added challenge of doing this silently, or users will scroll on by.

Briggs suggests companies start putting subtitles on the first few frames to catch a viewer's attention. So next time you're creating a promo video, think about how the message would come across if it were a silent film. This can be an advantage, because you don't have to rely as heavily on headlines to entice users to click. Now you can use onscreen tricks like provocative images and mesmerizing graphics to capture attention.