Date: July 1983
The Moment: Other stations had played rap before KDAY, but it wasn't until the hiring of Greg "Mack" Macmillan as their program director and afternoon host that everything changed. Mack turned the station into a hip-hop powerhouse, recruiting young talent to not only to DJ, but to have their ears to the streets. One such talent pool? The World Class Wreckin' Cru, whose Dr. Dre had started to mix tracks together on a mixer in real time, splicing old tracks into contemporary rap records.
The Impact: The station became one of the most influential outlets for rap nearly overnight, and broke some of the most important records in the history of rap. Moreover, it created the market for rap radio formats, and if hot rap singles begin anywhere, it's on rap format radio.
The Upshot: KDAY would eventually turn over from a rap format station in 1991, and would relaunch as a less-influential version of the original in 2004 as a middle-ground urban contemporary station. More importantly, however, KDAY lead terrestrial radio executives to realize that the rap format would be a crucial one in years to come, spawning the creation of rap radio all over America.