Guest Penguin Egg makes a generalisation that doesn't fit with my experience. Sure there are some folk clubs that are a bit cliquey and if you're an outsider you may feel you're not welcome. But many others are friendly to strangers - I went to one recently and the organiser made a point of asking me if I sing, and then invited me to do a floor spot. He needn't have done this as there were more than enough other performers to fill the bill. The regulars were very friendly. I've been to more friendly clubs than cliquey ones, on balance. Don't think they're all the same, GPE, try more clubs until you find one you like!