[cc-licenses] Requirements for a strong copyleft license

Erik Moeller erik at wikimedia.org
Sat Dec 1 20:22:55 EST 2007

(This is a posting to multiple lists.)

As you've probably read, the Wikimedia Foundation has agreed in
principle to support an update of Wikipedia content from the GFDL to
CC-BY-SA, pending a community approval of such a migration. The FSF
and Creative Commons are supporting us to make this transition

One open issue is the way both the GFDL and CC-BY-SA deal with
embedded media files like images, sounds, and videos. The FSF
interprets the GFDL so that e.g. a photograph embedded into an article
would require the article to be "copyleft" under the GFDL; Creative
Commons does not interpret CC-BY-SA in this fashion (at least
according to some public statements).

The actual clauses are very similar, however, and I believe what is
really needed is a license that gives authors the choice of "strong
copyleft" for embedded media: the work into which the media are
embedded (whether either work is text, sound, film, a rich media mix,
or whatever) should be licensed under a copyleft license.

Wikimedia could then allow contributors of multimedia to choose this
license, and to change files under the GFDL (as opposed to text) to

>From _my_ point of view, the key requirements are:

* It should apply to any type of embedded media, i.e. not limited just
to photos embedded into text;
* It should, in principle, be very similar to the CC-BY-SA license,
except for its provision on "Collections";
* It should be adaptable to as many legal frameworks as possible;
* IMPORTANT - I believe it should allow mixing of similar licenses,
e.g. CC-BY-SA into BSD -- the Definition of Free Cultural Works
endorsed by Wikimedia could be a guideline as to which licenses can be
mixed: http://freedomdefined.org/Definition

I would like to kickstart the discussion to get a first for such a
license - it could be called CC-BY-SA+ - written as soon as possible.
:-) Perhaps we should have a dedicated mailing list where stakeholders
from multiple projects can discuss it?

Erik Möller
Member of the Board, Wikimedia Foundation

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