Disseminating hate is not confined to the radio, although as already pointed out this medium has the most impact. "Written hate" as opposed to "broadcast hate" leaves a more indelible impression as the words can be read over and over again and absorbed.
The most notorious hate radio in the Great Lakes region of Rwanda was Radio Television Libre des Mille Collines. Established in mid-1993, it attracted many listeners because it played good music and was "chatty and lively" compared to the rather staid state-owned Radio Rwanda. Privately-owned, with some of the major shareholders belonging to ex-president Juvenal Habyarimana's family, it became a vehicle for inciting the slaughter that followed his death, calling for a "final war" and for "exterminating the inyenzi (cockroaches)". It broadcast lists of people to be hunted down and exterminated. Consequently, some of the biggest names associated with the radio are on trial at the International Criminal Tribunal for Rwanda.
Hate radio is one of the "outgrowths" of relaxing radio controls in Africa where private stations are constantly springing up. Whilst hate radio can cross the line between freedom of expression and incitement, the genocides in Rwanda and Burundi would have gone ahead with or without the radios.