Via Xeni Jardin of boingboing, a flag we can wave proudly today
Lawrence Lessig , Professor of Law at Stanford Law School, and founder of the Creative Commons, has just shared that the Court of Appeals for the Federal Circuit, or what he calls "THE "IP" court in the US," has "upheld a free (ok, they call them "open source") copyright license, explicitly pointing to the work of Creative Commons and others. (The specific license at issue was the Artistic License.)"
He goes on to explain that, "in non-technical terms, the Court has held that free licenses, such as the CC licenses, set conditions (rather than covenants) on the use of copyrighted work. When you violate the condition, the license disappears, meaning you're simply a copyright infringer. This is the theory of the GPL and all CC licenses. Put precisely, whether or not they are also contracts, they are copyright licenses which expire if you fail to abide by the terms of the license. Important clarity and certainty by a critically important US Court."
Mike Gunderloy provides a good explanation of it on the Ostatic blog.