Picked up on the term "folk-filk" in your reply to AG. "Filk" is a term as old as I am, but I've only been familiar with it for five hours. I'd expect dubdobdee to have greater knowledge. Is there any crossover to indie? The Wikip filk writeup is stingy in naming performers or recordings. Tom Lehrer, who seems to have nothing to do with filk culture, nonetheless is cited; as is Pete Seeger and Arlo Guthrie, neither of whom are particularly AC (maybe Arlo has his AC moments; his cover of "City Of New Orleans" probably gets AC airplay).