I wonder why it is historically that we have a thread here debating trad v singer/song-writer. If you wind the clock back 50 years, and look at the British or American folk revival. you would see a lot of people in folk clubs etc who shared an interest in folk music. They also, naturally, had interests in other genres ofmusic, which would also get the odd airing at the clubs. So mixed with the folk music you would get the occasional bit of barber shop,jazz, fiddlers playing Flight of the Bumble Bee,rock'n'roll, self-penned songs etc etc. Finer and dandy.
    OK, fast forward to now. Those occasional people trying out the odd song they've written have now become so important numerically that, judging by this thread, they have actually driven out the folk music from the festivals. But why them? Why not the barbershop enthusiasts? Why didnt punk rock take over folk festivals? Or flamenco guitarists? Gregorian chant? Intriguing, eh?