If you see a Facebook ad from American Express, that’s exactly what you should be doing. Like other hacks of Facebook’s silent autoplay videos, AmEx released an ad that changes the experience if you listen to the ad with the volume on or off.
This one rewards you a prize of sorts if you turn up — no, not like that — the volume to hear the voice-over. So keep your ears peeled the next time you see an ad from AmEx. They could be making it worth your while.