I would refer anyone with an interest in this subject to the excellent article sited by Kath Westra in the Dave Van Ronk thread. Here is an excerpt...

Although the building blocks of oral culture are plastic, preservationists in a nonoral culture tend toward reverence, and thus simpler imitation--hence the folk revival's slew of earnest groups like the New Lost City Ramblers. As Van Ronk observed in a late 1970s interview in the folk music quarterly Sing Out!, "It was all part and parcel of the big left turn middle-class college students were making.... So we owe it all to Rosa Parks." While black rhythm-and-blues was revving white teens into rock and roll, black folk artists became heroes to young white collegians. The left cast a romantic, even sacramental aura over black (and white) folk art and its traditions, which implicitly stigmatized creative change; the central notion of folk-revival culture, authenticity, meant avoiding commercial trappings and replicating a recorded past.