"Ephemeral literature" is the term that has been used for the so called "urban folklore" genre and that is evidently a loan from the concept "ephemeral art". They are originally popular compositions of oral transmission (primary) or oral compositions related with writing on not so conventional and different platforms to books, paper or Internet (sometimes, mixed oral transmission; others, secondary), important for reflecting social ideology and popular creativity ("ingenious feature" in Jolles classification of simple forms). Artisitically it is an genre lacking prestige and, even frequently neglected and destined to be cast into oblivion, but that is part of our everyday life and reflects the collective imagination with great spontaneity and radicalism, remaining anonymous, of course. In the Archive we have distinguished four subgenres: songs in mass public performances, "contrafacta" or re-elaborated compositions from traditional wel-known forms, written forms of mixed and secondary oral transmission (dedicated folders, wall-paintings, inscriptions, graffittis, decorated envelopes, tattoes, SMS messages, etc.) and other forms where manifestations of ephemeral literature difficult to classify have been included.