When I first began to consciously listen to FM radio in the New York area (in the late 1980s and early 1990s), the breakdown of music stations was similar to what it is today. There were a bunch of "current hits" stations, some modern rock/alternative, hip-hop/rap, and a few other random but current music genres. There was one major difference: the oldies. At that time, the oldies were considered to include popular music from the 1940s, 1950s, and early 1960s. Today the oldies on FM radio primarily include classic rock from the late 1960s, 1970s, and early 1980s.
This transition probably occurred somewhere in the mid-1990s due to the major generational shifts at the time - i.e. the Baby Boomers beginning to dominate the nostalgia/oldies market following the near-complete retirement (and decreased oldies consumption) of the Greatest and the Silent generations. There wasn't enough FM radio spectrum to cover all music from the 1930s through the early 1980s under the oldies umbrella, so station owners focused on the consumers that mattered most at the time.
When a similar consumer-driven generational power shift occurred with the most prominent modern form of content delivery, the Internet, old content didn't disappear but only took a back seat. When Generation Y came to dominate Generation X in Internet content-consumption, the Internet just became bigger, richer, and better.
This relatively innocuous comparison reinforces an important lesson about today's main platform for communication, the Internet. Terrestrial FM radio is limited by the radio spectrum used to broadcast its tunes. The Internet is reaching a point where such delivery-limitations are quickly becoming nonexistent. This is why most new Internet content is stacked on top of old content - i.e. why Yahoo and AOL still exist alongside Google and Facebook.
This means that the Internet can't be really compared to any previous form of content-delivery platforms such as letters, pamphlets, newspapers, books, radio, television, or even cable television. The Internet faces nearly no scarcity problems for either supply or demand. The greatest limitation becomes time - time for creation and time for consumption.
This creates a whole new context for evaluating and discussing the economics of Internet content and content-delivery - a massive topic that I will analyze more in the near-future.