I had some thoughts on radio after our discussion on Monday that I wanted to share here. My experience with radio has not been one of ephemerality, but of intentional listening and archiving. I don't believe that ephemerality is a necessary byproduct of the medium of radio, but a willful creation of circumstances that invoke such a feeling (not unlike the willful suspension of disbelief engaged in by an audience and participant in hypnosis). The detailed archives that I assume most radio stations keep would show the opportunity to repeat what happened in the studio at any point, much like the storage space on our computers lets us store and listen to podcasts.
I understand the collective experience of listeners to a radio program, but this is also a largely unidentifiable phenomenon with the exception of listening in the same physical space with a group and again requires a sort of suspension of disbelief. Internet radio stations give us real-time statistics (the number of simultaneous listeners to a station) that quantify the collective experience, but a collective listening experience is present in physical space or in the imagination.
The transmission of particular information via radio waves requires a physical infrastructure that eventually sends information wirelessly, which at this point is also the way that many of us receive the information that arrives on our computers. If radio stations have not made their archives available, on demand, to the listening public in the past, today's technology makes that kind of framework possible.