I hope everyone will allow me to get something off my chest. It's more along the lines of a pet peeve, actually.
Now I realize that this happens in genres other than folk but here goes: Why do people continually refer to songs as tunes? I think of tunes as melodies, which, granted songs have, but I specifically think of them as instrumental melodies. So an Irish reel, for example, is a tune (no lyrics). An Irish song is a song (has lyrics).
Okay, whew, I feel better now. Until the next time it happens.
I apologize if I ruffled any feathers and I realize that my comments have added nothing to the original idea of this thread but I couldn't help myself.