Licenses

The grid

License	Intended scope	Copyleft	Modifiability	Attribution	Worldwide applicability
Against DRM	-	?	?	?	?
CC BY	-	no	no	yes	national adaptations
CC BY-SA	-	yes	no	yes	national adaptations
Design Science	-	yes	yes	no	same license (English version)
Free Art License	-	yes	no	yes	exact translations
GNU FDL	text documents	yes	yes	no	same license (English version)
GNU GPL	software	yes	yes	no	same license (English version)

Criteria

Intended scope

Some licenses strive to be as generic as is humanly (or rather, legally) possible. Others deliberately focus on a specific domain of creation, like software, or documentation. When a license has such a focus, it doesn't mean that it cannot be used for other kinds of works, but that its main area of use (and thus its social recognition as a trustable license) is clearly bounded.

For example, the GNU GPL can be used for many kinds of works, but its main area of recognition is software.

Copyleft

When a work is "copylefted", it means all derived works (even if they mix in other works as well) must be distributed under the same terms (usually the same exact license) as the original work. Conversely, a non-copylefted work can be distributed under different terms, and even be rendered non-free.

Therefore, using a copyleft license pretty much guarantees that users of subsequent works (for example modified copies) will be granted the same essential freedoms. On the other hand, a copyleft license can also limit opportunities for re-use, because most copyleft licenses are not compatible between each other. This is why people sometimes prefer non-copyleft license, depending on the work and the kind of practices they want to encourage.

Note: ShareAlike is a synonym of copyleft in the Creative Commons vocabulary.

Modifiability

Although all free licenses give you the legal right to modify, not all of them try to specify how modifiability of the work is practically enforced. Requiring modifiability is important, especially for works which can be distributed under a completely opaque format such as software binary code ("object code").

The licenses which require practical modifiability usually define a notion of source code, source data or similar.

Attribution

Requiring attribution means that authorship for the work must be recognized in any circumstances. In the context of derived works (modified copies), this includes the initial as well as subsequent authors and contributors.

It may be argued that all licenses implicitly require attribution, as they mandate that the copyright notice must be kept intact when distributing copies. However, the copyright notice may not acknowledge authorship for all contributors (past and present), especially if the legal copyright holder is an organization.

Attribution is a double-edged sword, as it may become a very heavy burden to list all contributors for projects implying seamless and massive collaboration (like Wikipedia). For most works it is a however a reasonable requirement.

Worldwide applicability

When distributing a free work over the world, it is important to understand how people from other countries will be able to reuse this work.

License writers have adopted three different strategies regarding the internationalization of their licenses:

• same license for everyone: only the original license text (often in English) is given legal value, and translations may be provided purely for information purposes;
• exact translations: translations of the original license text are provided, which all have legal value; those translations have exactly the same clauses and wording as the original text;
• local adaptations: the license is rewritten according to each national legal system.

The two first schemes ensure that everyone is given the same rights. In the third scheme (local adaptations), similarity and equivalence of the different versions should be carefully examined.

According to advocates of the adaptation scheme, licenses must be rewritten in order to cope with the peculiarities of the various legal systems. This position is held by the Creative Commons organization.

According to opponents of the adaptation scheme, having different national versions of a license presents the risk to break trust and interoperability. Also, they stress that the Berne Convention for the Protection of Literary and Artistic Works provides a framework which, with careful drafting, allows to write internationally applicable license texts. This position is held by the Free Software Foundation and by the Free Art License authors.

License list

Against DRM

• current version: 2.0

Creative Commons licenses

Creative Commons BY

• complete name: Creative Commons Attribution
• current version: 2.5

Creative Commons BY-SA

• complete name: Creative Commons Attribution-ShareAlike
• current version: 2.5

Design Science License

• not maintained anymore
• reference URL: http://www.gnu.org/licenses/dsl.html

Free Art License

• current version: 1.2
• reference URL (English): http://artlibre.org/licence/lal/en/
• reference URL (French): http://artlibre.org/licence/lal/

GNU FDL

• complete name: GNU Free Documentation License
• current version: 1.2
• reference URL: http://www.gnu.org/copyleft/gpl.html

GNU GPL

• complete name: GNU General Public License
• current version: 2.0
• reference URL: http://www.gnu.org/copyleft/fdl.html

(to be removed when the page overhaul is finished)

Current draft

Tentatively, the following licenses are known to meet the criteria set out by the definition:

• Creative Commons Attribution License (not free for Debian)
• Creative Commons Attribution/Share-Alike License (not free for Debian)
• GNU Free Documentation License when no invariant sections are specified (this is important)
• Free Art License (not free for Debian)
• Against DRM 2.0
• All free software licenses. While many of them are specific to software, some are worded so as to apply to all kinds of digital works. For example, the GNU GPL is often applied to non-software works (such as computer graphics, game scenarios...).

In addition, works in the public domain are also free content as per the definition.

To be verified:

• Freie Wiki-Lizenz

Controversial:

• IANG license - seeks to enforce lots of things that are outside of the copyright realm (like organization scheme, right of developers to have a voice in the development process, etc.)