One thing I read (posibly in the Oxford Book of Carols, but I could be wrong)that rang a bell for me was that the folk process had created "hardwearing" songs. That sounds a bit worthy and dull, but it's very true, and to me it's one of the reasons the songs are often so compelling.

All that tweaking and editing that has taken place over the years, cutting out some of the rubbish and sometimes adding improvements, has left us with lyrics and tunes which are strong enough to stand on their own and be used and interpreted in different ways without losing their identity.

Many pop songs, by comparison (and let's leave the Beatles out of this for the moment, they're a bit of an exception) depend largely or entirely on one interpretation or one chacteristic guitar riff or backing vocal; once you deconstruct the pop song a bit, you often find you're left with nothing of substance (as in the Bee Gees example you gave).

Traditional songs (and tunes), on the other hand, have often evolved and developed an integrity and an inner strength that enables them to be performed by a single voice or instrument, by an informal group, or by a multi-piece band, and still survive as recognisable songs or tunes. That's one thing I love about them.

Marje