Someone who broadcasts a radio signal, usually on the FM band, at very low power. The corporate media usually call microbroadcasters pirates, but they're mostly scared of what will happen to their audience once someone dares to play more than the top 40.

Corporate radio stations often claim that microbroadcasters' 10-watt signals cause interference with their own 100,000-watt signals. Microbroadcasters know this is bullshit; if they weren't in a dead area of the radio dial to begin with, nobody would ever hear the signal.