For those of us dedicated to creating, expanding and enabling a commons of creativity and knowledge (expressed in a variety of formats), the issue of license interoperability is an important one. Already there has been valuable commentary about the interoperability between content licensed under different types of Creative Commons licenses — specifically, those that permit both commercial and noncommercial uses and those that restrict use to noncommercial uses only. These concerns are valid and important, and we are working to address them in our FAQ and general messaging. It is critical that license adopters make a sufficiently informed choice about which license satisfies their requirements, and that they understand the consequences of their license selection _before_ they choose a license.

However there is another — arguably more pressing — interoperability issue that arises in the context of content licensed under a Creative Commons license and content licensed under other “free” licenses. As many of these licenses are now crafted, there is no way for creativity to be shared among these licenses, even if the underlying freedoms guaranteed by the licenses are the same.

Thus, for example, Wikipedia is licensed under the Free Software Foundation’s GFDL. That license essentially enables the same freedoms as the Creative Commons Attribution-ShareAlike license; but you can’t take content from Wikipedia and mix it with BY-SA photos from Flickr because the licenses don’t permit interoperability. Even though the underlying freedoms are the same, the legal codes make the content non-interoperability.

We want to fix this problem. Over the next few months, Creative Commons will be announcing a project to facilitate the federation of free licenses. Our aim is to make the legal code of those licenses interoperable. We will be working with as many representatives from the free culture movement as we can to build this federation of free licenses. We will appreciate your advice and feedback as we do that.

Today we are launching a discussion as a small first step towards that interoperability. This is by no means a solution to the general problem. But it is an effort to smooth the differences between two of the most important free license families.

Many have talked about dual-licensing as a solution to the interoperability problem. That is a good first step, but it raises obvious problem that has been eloquently discussed on our cc-licenses list — namely, that whichever license you take content under, any derivatives that you make must then stay under that license.

To solve that problem, and to begin this discussion of license interoperability, Creative Commons seeks comment on proposed amendments to Creative Commons licenses that contain a ShareAlike license element. These amendments would enable dual licensing of derivatives. By proposing (and hopefully effecting) the amendments posted here, Creative Commons hopes to enable interoperability between “free” content licenses, encourage dual licensing of open content projects and avoid the depletion those projects by barring the return of derivatives to that project. Again, this is not a long term solution. But while we begin the process of discussion to find that long term solution, we believe this will help many important free culture projects achieve a limited interoperability immediately. We are committed to doing whatever we can to assure that creative work licensed freely can move as freely among licenses as the principles embedded in those licenses will allow.

Please circulate your comments to and participate in the debate on the cc-licenses list.