Even before the launch of MTV, the music video has been making pop songs buzzworthy. And since the early ’80s, it has transformed also-rans into hitmakers—from the Buggles and Duran Duran to Peter Gabriel and a‑ha. But until the early 2010s, watching a video didn’t count on the Billboard charts. That all changed thanks to YouTube—and the biggest immediate beneficiary from the addition of video to the charts was a rising pop star, incubated on the Disney Channel, but looking to change her image. Miley Cyrus was born into hitmaking, line-dancing, multimedia royalty, and she used video titillation—and even the social site Chatroulette—to top the charts. But what did all that provocation mean for…y’know, the music? And how is video still making hits—including the song that’s No. 1 this very week in 2018?  Chris Molanphy explains it all. hitparade@slate.comLearn more about your ad choices. Visit megaphone.fm/adchoices