When I was a kid I was fascinated by pirate radio stations. Occasionally we would hear a pirate station or two on the FM broadcast band playing odd music and going by fun DJ nicknames. Later when I got to college the trend continued. However, the stations seemed to be more interested in talk of politics and media censorship than playing any music. The media censorship argument was simply that the pirates felt they had no way to disseminate local information they decided was not being covered by large broadcast networks. They typically defined "local" to mean a few city blocks/square miles. Eventually the FCC addressed this need by creating the Low Power FM (LPFM) Service.
In the 90's you could be certain that everyone had access to a television and an AM/FM radio receiver but little more. Today a very large percentage of people have cells, laptops, and desktops with access to WIFI. A pirate today might use a wireless access point without an Internet connection to forward all http requests to a broadcast server web page. The computer would serve useful local information with a link to receive streaming audio (Shoutcast). The audio stream could either be pre-recorded or live with interesting local content. The station might even use familiar SSID's (102.1FM) to encourage listeners to log on. The size and coverage of the pirate radio network could be expanded considerably by adding more access points. The pirate radio network could even support multiple stations for different categories of listeners. It seems to me that in many areas a concept like this might be very popular.