Many have written about the email legends that are passed around over and over again, and the wonderful Snopes website that helps to clear up these interesting stories. But, in addition to the written stories, many legends have been written about in music.
Take for instance, the song Deck of Cards done by Tex Ritter. This is a song that has always interested me, simply because of the words. Feel free to click on the link to read the words, but to summarize, a soldier, after being on a long march, attends church services. The soldiers pull out their prayer books, however this particular soldier has only a deck of cards which he pulls out instead. He is brought before the martial for playing cards in church, and explains how one deck of cards is a bible, a prayer book, and an almanac. However, as you can see by reading the words at the end, it's pretty obvious that this isn't a true recount of a story since Tex states that, "I knew that soldier". Given the timeframe, it would seem that this just isn't possible. But the words are good, it tells a very convincing story, and it makes people feel good.
There's another song that, while it has actually been confirmed to be true, tells an amazing story. Christmas in the Trenches, sung by John McCutcheon tells the story of the 1914 World War I truce between England and France for one night. This song, copyright 1984, does an incredible job of describing something that has happened only once. If you can get the audio, there is a version where John talks briefly about the song, how it came to him, and an experience he had after writing it. Without facts backing the authenticity of this 1914 Christmas, John's song could very well have also gone down as being an urban legend.
It is important to know the difference between truth and, let's call it exaggerated truth for the sake of argument here. In my first example you can see how the story told makes sense, it sounds good, but most likely just isn't. The second example is a true story, even if it's being told by someone who wasn't there and couldn't possibly know, but somehow managed to create an incredibly powerful description anyway. Urban legends have been used for centuries to entertain, and they definitely do, as long as the story doesn't cause harmful things to happen to those who take it seriously.