CC0
= one of the Open Scientific Data Licenses, part of the Creative Commons
URL = http://wiki.creativecommons.org/CC0
Discussion
How is CC0 different from the Public Domain Dedication and License (“PDDL”) published by Open Data Commons?
"The PDDL is intended only for use with databases and the data they contain. CC0 may be used for any type of content protected by copyright, such as journal articles, educational materials, books, music, and art, as well as databases and data. And just like our licenses, CC0 has the added benefit of being expressed in three ways: through a human-readable deed (a plain-language summary of CC0), the legal code, and digital code. The digital code is a machine-readable translation of CC0 that helps search engines and other applications identify CC0 works by their terms of use."
(http://wiki.creativecommons.org/CC0)