Domas Mituzas writes in an extremely nice post:

It takes time to understand one is ‘creative commoner’. I do have a t-shirt with such caption, but it is much more comfortable once you start feeling real power of use and reuse of information. Few anecdotes…

He tells stories of the joy of being reused (see our last post on that subject for similar).

Mituzas recognizes the importance of standard copyright licenses in facilitating such reuse…

Also, by using CC license I simply used lingua-franca of world I’m in – and now my content can evolve into shapes that I couldn’t expect, and that would be limited by non-portable licenses.

…and the problems posed by non-interoperable licenses:

Of course, there other different stories. My colleague (and manager) runs a wiki about his own town, Bielepedia, and he wants to exchange information with Wikipedia. Now he can’t, as well as quite a lot of other free content community projects. Though of course, some may believe license difference doesn’t mean much, in this case it means that we’re building borders we don’t need nor we have intent to maintain.

Indeed, one of Mituzas’ points is that Wikipedia should migrate to CC BY-SA (he is an active Wikipedian and Wikimedia Foundation board member, also see the migration decision timeline and our most recent post on the matter).

Unnecessary licensing incompatibility between Wikipedia and much of the rest of the free content world not only prevents specific reuses, but probably hampers the growth of free content overall, as mentioned in the Creative Commons Statement of Intent for Attribution-ShareAlike Licenses:

When a copyleft license is widely used, it not only protects essential freedoms for all users, it fosters the spread of those freedoms. This occurs when people who may not know or care about Freedom as understood by the Free Software movement, but merely wish to use works that happen to be Free, release adaptations under a Free license in order to fulfill the requirements of the license. By the same token, if there are pools of Free content that may not be mixed because their copyleft style licenses are legally incompatible, the spread of essential freedoms is constricted.

However, it’s important to note that Bielepedia, as currently licensed, would not benefit from the migration of Wikipedia to CC BY-SA. That’s because Bielepedia is licensed under CC BY-NC-SA. Hopefully inspired by the possibility of interoperability with Wikipedia, Bielepedia and many other projects will see fit to migrate to more liberal CC licences that are interoperable with CC BY-SA and meet the WIkimedia Foundation’s licensing policy (CC BY, CC BY-SA, and CC0/public domain, though the latter aren’t licenses).

If you haven’t yet please go read Domas Mituzas’ post on being a creative commoner. It really is very nice!