Lyor Cohen started his career as a roadie for Run DMC and went on to head Def Jam Records when it was home to the likes of Jay-Z and DMX. With that experience, followed by a chief executive gig at Warner Music Group through 2012, he helped create the soundtrack that would play an important role in propelling hip-hop music from niche to mainstream to everywhere. Now coming up on 5 years as YouTube’s global head of music, Cohen shares his views on the place of record companies today, including who should be running Def Jam, and offers his thoughts on Rock and Roll Hall of Fame contender LL Cool J, the recent passing of rapper DMX and of Cardi B's "Wet Ass P—."