Creative Commons

Creative Commons was founded on the notion that some people may not want to exercise all of the intellectual property rights the law affords them (works are automatically copyrighted)

Defines a set of human and machine readable (RDF/XML) public licenses

Attribution.

Non-commercial.

No Derivative Works.

Copyleft.

Defines a means for describing works (Dublin Core and Creative Commons) in RDF/XML and associating licenses with works