Go beyond streaming and MP3s with .m4a which have chapters, illustrations, live web links and makes for "stiky" media.
Traditional broadcast media are not connected.
Internet shows relying on MP3s are, (except when they are on an unlinked portable device, [which is a slowly disappearing category because of the iPod Touch and other products,])
But even linked shows aren't making full use of the potential of the media unless they are using the .m4a file format which divides up the content in chapters, (its just the name they used,) and can associate images (.JPGs or .TIFF [and potentially .MPGs and .MOVs]) and can also associate "hot" web links with whatever content is in the .M4A file.
We go from a forcedly stand alone file, and experience, to one which can be as rich as possible.