I had been talking about “limited duration” copyright for quite some time, and lo and behind, Creative Commons has done something about that. Founder’s copyright sets a time limit for copyright ownership (14 years) and allows authors to extend this exclusive copyright for another 14 years. After 14 years (or 28) everything reverts to creative commons/public domain. Speaking of what’s new at CC, they now have a developing nations’ license (allowing free copies by people living in developing nations).
I learned about this while listening to a Bloggercon III discussion led by Larry Lessig.