If I want to know whether someone's a folk singer or not I always look at the top end of their guitar. If there are three of those twirly knob thingies sticking out on each side it's a folk singer. But if all the knob thingies are on one side in a sort of slanty row it's a rock star. Easy. Unless it's Billy Bragg. There's always one awkward sod, isn't there?