Until recently, creative people have had two options in sharing our work: copyrighting it and reserving all rights, or releasing it to the public domain. The first option means anyone who wants to copy, republish, or adapt that work has to ask permission and maybe negotiate some sort of fee or contract. The second means anyone can do anything, including selling the work for their own profit, with no compensation to the original creator.
Not surprisingly, most people have stuck with rights-reserved copyrights. Open-source and free software advocates have modified that into a shared resource using "copyleft," but Creative Commons takes a more nuanced approach to a wider variety of materials. It's a marvelous idea, with a huge buzz among techies since its first public release earlier this week.
I'll soon figure out how to apply Creative Commons licenses to material on this site. The Internet is about sharing, and I'd like to figure out how to do it better.