We need net "radio" that pulls its content, as-needed, from a P2P sharing space.
The "broadcaster" would really just provide an ever-refreshing playlist, a window on the last X minutes of contiguous content, with reliable (hash) identifiers naming each segment of media to play. "Tuners" would fetch the playlist, and scour any and all available sources for matching content fragments, grabbing them seconds to minutes before they are needed, playing them for the local listener in order and without gaps, resharing them for as long as possible, discarding them when necessary.
Some of the fragments might be content that is already widely available (popular tracks), perhaps listed as a series of acceptable alternates, while other fragments would be custom content, recorded and shared out over P2P networks nearly-live.
Call it "Judio", for "Judo-radio", because it emphasizes the use of a tiny, smart control channel to leverage a giant amount of content on outside networks. Generalization to video or other media content is an obvious extension. Latest-on-top blogs/feeds are the new broadcast networks, and all that jazz.
Gnutella and other P2P networks could conceivably be (or grow into) the role of being the content-cloud.
Would a station publishing such a playlist require a broadcasting license for the copyrighted content to which they refer? They are not making any copies; that is left up to the listeners.