I think in a forum like this, though we may not be able to come up with a universal definition of folk music, we all pretty much know what we mean. We may argue vehemently about where to put the fences but we all know what we want to fence in.

The bigger problem, though, is that the general public doesn't have a clue. In Boston there are quite a few "folk" shows on the radio but the music is about 98% singer/songwriter. I think that this is how folk music is perceived in the 90's: serious political or excruciatingly personal songs which are instantly forgetable. The antithisis of any reaonable definition of folk music.

Celtic music, Appalchian music, traditional African-American music, Cajun, etc., etc. appear on the radio in their own specialty shows. A comtemporary American audience would not see the connection in these muscial forms and would certainly not call them "folk."