Underground radio

Here's a tantalizing line from an article on Garrison Keillor:

Keillor has called radio "an underground reality"...

One can infer where this is coming from, largely the nature of radio in a mediasphere dominated by other forms.  There's a touch of ethnography, too, as this New York press article notes, with public radio staffers coming from college and underground radio.  So, a nice mix of subversion, anticommercialism, and historical longing.

If you want to look at underground and otherwise anti-mainstream radio, the best place to turn is Jesse Walker's Rebels of the Air.