Howard - The difficulty I have with this approach is that in order for people to get together "in the spirit of folk", or for them to decide to designate their event as a "folk" club or "folk" festival, or even if just in their own mind what they are doing is "folk", they must have some concept in their mind of what "folk" is.

Oddly enough I don't have any difficulty with this, partly because I've seen it happen. Week 1: a Folk Club is announced; six singer-songwriters, one traddie and a hopeful who knows a couple of Dylan songs turn up, and do three songs each (the last guy struggling a bit with the third one). Week 2: eight singer-songwriters, two traddies and two hopefuls turn up and do two songs each. Week 92: 16 singer-songwriters, four traddies and eight hopefuls turn up and do one number each. What you can expect one week is mostly determined by what went on in the previous weeks, which in turn was mostly determined by what had gone on before. It's a self-sustaining, iterative mechanism, sustained by feeding on itself and on innovators who wander in. You could call it the folk club process...