Urban legends Definition:

Urban legends are a kind of folklore consisting of stories often thought to be factual by those circulating them. Urban legends are sometimes repeated in news stories and, in recent years, distributed by email. People frequently say such tales happened to a "friend of a friend" - so often, in fact, that FOAF has become a commonly used acronym to describe this sort of story. Urban legends are not necessarily untrue, but they are often false, distorted, exaggerated, or sensationalized. (from wicki)

Urban Legends Secondary Definition:

Universal motifs in folklore, or stories to good to be true. Urban legends are friend-of-a-friend stories (FOAFS) that are told to describe strange, but supposedly real events, when in fact they are fictional due to word of mouth invention or distortion. There is usually a true element to the legend, but it becomes fictional as it is passed from one person to the next. Core elements in most urban legends remain the same, but details of the story can differ from one locale to the next.

The difference between an urban legend and an internet scam is that while both attempt to deceive the reader, urban legends do not attempt to separate you from your hard earned money, unless you count throwing out all your glade plugins.

Visit the Urban Legends Reference Page for a list of popular email urban legends by category.