WAV's thread has started a discussion that has been very informative--I have been curious about the role of instrumental accompaniment in the various UK folk traditions, and have always been dubious of the idea that unaccompanied singing was some sort of cultural universal.

Music spreads easily, and the idea that in something must be popular before it can become traditional makes a lot of sense to me--in a way, the idea of "traditional" music ignores the fact that music is primarily disseminated laterally, that is, within a culture, in a place and time--Paul Simon said that "Every generation sends a hero up the pop charts", and the evidence is that it has ever been so--