Credit Where Credit is Due, an article in Newsweek, about use of text from Wikipedia by major publishers without compliance with Wikipedia’s license, includes quotes from CC CEO Lawrence Lessig on license interoperability:

The Free Software Foundation, which maintains Wikipedia’s GNU license, is teaming up with a popular rival licensing movement called Creative Commons to create an interoperable open source standard. “This has been my secret obsession and work for the last four years,” says Lawrence Lessig, a Creative Commons founder and Stanford University law professor. “Make the legal issues totally invisible to the average user who is trying to use free culture in a way that is responsible and trustable.” By making the two licenses interoperable, for example, users will be able to integrate text, photographs and music samples from Wikipedia with Creative Commons-licensed content on Flickr or jamendo. Posting, reprinting, sharing and otherwise licensing such material would simply require attribution (and not the actual clunky text of the license).

The article’s closes with an excellent suggestion:

It’s enough to suggest that, for penance, Wiley ought to commission “Open Access for Dummies.” Published under a Creative Commons license, naturally.

Read the whole article and previous writing of Lessig on interoperability and details of compatibility structures introduced in CC BY-SA 3.0.