It is also interesting to listen to "folk-singers'" versions of songs that were note originally "folk"
Dick Gaughan made the Rolling Stones' Ruby Tuesday into a superb "folk-song".
Norma Waterson's solo CDs have interpreted many songs really well. As has June Tabor's 'non-folk' stuff.
What it comes down to is there is that there is no black and white, just a very large area with differing amounts of grey. The problem comes when people want to impose strict definitions which eventually begin to contradict themselves which is clear from a different thread on the Mudcat. However, if it is good music it will stand the test of time, no matter what the label. People are arguing over the label, which at least, shouldn't detract from a whole load of excellent music
Cheers
Rana