A derivative of the term "broadcasting", narrowcasting is the delivery of messages to a select audience.
First used in broadcast media, the technique often relied on resonance to attract the attention of select audience members to a message most other listeners or viewers will ignore.
More recently, narrowcasting has involved the use of new electronic media to deliver messages that might invoke widespread negative responses if broadcast to a more general audience through more traditional electronic broadcast media. Propagandists sometimes find narrowcasting to a select audience to be more cost effective than traditional broadcast tactics.
Also see political microtargeting.