"I have never come across one great, overarching 'Tradition'. A huge range of more or less local traditions, certainly, but nothing that encompasses them all."

A fair point, but if the same kind of thing was going on at local level in thousands of different places - for example the old 'Scarborough Fair' / 'Cambric Shirt' song being passed on orally through the generations in North Yorkshire, New England and the Ozark Mountains, then I think it's valid to see an overarching process there. The term 'The Tradition' is sometimes used a bit carelessly, usually as shorthand for "the kind of thing that used to happen", as SOP has been explaining.

[In your last post, Suibhne, you seemed to get perilously close to endorsing the concepts of Folk Song and Folk Lore. Surely not! Several nice posts from you, though - and overall a more civilised discussion than some I've seen here]