Rog, assuming you're being serious in asking, I think you must be getting the idea that a "traditional" song is indefinable because anyone can think up a number of parameters to describe them, all of them quite reasonable, but many of these parameters are mutually exclusive of each other. A L Lloyd wrote some songs which are accepted by most people as traditional, but not by others because they aren't anonymous. Others say that oral transmission with all its variations is the main thing, while some say that only a proven written record is acceptable and singers must preserve them word-perfect. Or you could say that only songs sung on traditional occasions are the real thing, and that "Happy birthday to you" is as traditional as "God rest ye merry gentlemen". Name any song you think is traditional and someone will give you a perfectly good reason why it isn't. Might as well try to nail a rainbow to the wall.   

Some people used to kill butterflies and put them in display cases because they thought they looked prettier like that; others prefer to watch them flying around.