Black Entertainment Television. Originally a once-a-week offering that showed lost cinema classics (and คาสิโนออนไลน์เครดิตฟรี not-so-classics) featuring black directors and performers, they became a full-fledged cable network sometime in the 80's.
They showcased rap, Michael Jackson, and Prince long before MTV championed them (IIRC). BET's success is supposed to be a triumph of narrowcasting, but it's not really a triumph at all - like MTV, it's just as mass-market in mindset as any broadcaster.