[cc-licenses] Most important feature: GPL-compatibility

Francesco Poli invernomuto at paranoici.org
Wed Dec 28 16:44:43 EST 2011

Hi all,
you may remember me from my comments on the CC-v3.0 drafts on this same
list, back in 2006-2007.
Please note that, even though I am a contributor to the Debian Project
and I often speak from the perspective of the Debian Free Software
Guidelines (DFSG), I do *not* speak on behalf of the Debian Project.

That said, I would like to contribute to the CC-v4.0 requirement

In my own personal opinion, the most important feature that really has
to be implemented into CC-v4.0 licenses is GPL-compatibility.

The reason is that the Creative Commons project should strive to reduce
barriers to the re-mixing and re-combining of existing works, by
maximizing compatibility with other well-known licenses: the GNU GPL is
the most prominent and important example of such other licenses.
This strategy will result in a more effective commons of re-usable and
re-adaptable works for the greater benefit of the community.
Many examples of scenarios where this is important could be described,
but one is especially crucial: in the context of Free Software games,
it is not unusual to see cases where the distinction between game
engine and game data is blurred, rather than clear cut.
In these cases, having parts of the game licensed under the terms of
the GNU GPL and parts under the terms of CC-by-sa (or CC-by) may create
compatibility issues and/or legal uncertainty, which may significantly
slow down the development of the game itself.

How can GPL-compatibility be implemented into CC-v4.0 licenses?

I think the only possible approach is including an explicit one-way
conversion clause.
Of course GPL-compatibility can be implemented only for CC-by-sa and
for CC-by licenses. More restrictive CC licenses (those with nd and/or
nc clauses) cannot be made GPL-compatible, without completely changing
their intended effect.

Hence, I think that:

  * CC-by-sa-v4.0 should include an explicit one-way conversion clause
that would allow redistribution of the work under the terms of the GNU
GPL version 2 or any later version

  * CC-by-v4.0 should include an explicit one-way conversion clause
that would allow redistribution of the work under the terms of the zlib
license: http://www.gzip.org/zlib/zlib_license.html

I chose the zlib license, since it's a simple permissive non-copyleft
license which is GPL-compatible. Another similar license could be
chosen as well, if considered more suitable (for example the Expat
license: http://www.jclark.com/xml/copying.txt   or the 3-clause BSD
license: http://www.debian.org/misc/bsd.license).

I hope these suggestions make sense to you.
I would really love seeing them implemented in the next drafts of
CC-v4.0 licenses.

All the best,

 New GnuPG key, see the transition document!
..................................................... Francesco Poli .
 GnuPG key fpr == CA01 1147 9CD2 EFDF FB82  3925 3E1C 27E1 1F69 BFFE
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