GNU Free Documentation License facts for kids

Quick facts for kids
GNU Free Documentation License

The GFDL logo
Author	Free Software Foundation
Version	1.3
Published	November 3, 2008 (current version)
DFSG compatible	Yes, with no invariant sections (see below)
GPL compatible	No
Copyleft	Yes
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The GNU Free Documentation License (often called GNU FDL or GFDL) is a special set of rules for documents. It's like a permission slip that tells you what you can do with a piece of writing. The Free Software Foundation (FSF) created it for the GNU Project.

This license is similar to the GNU General Public License, which is for computer programs. The GFDL lets people copy, share, and even change a document. The main rule is that any new copies or changes must also follow the same GFDL rules. You can even sell copies of the document. But if you make many copies (more than 100), you must also share the original document or its source code.

The GFDL was first made for things like user guides, textbooks, and other learning materials. It's also used for documents that come with GNU software. However, it can be used for any kind of text. For example, the online encyclopedia Wikipedia uses the GFDL for most of its articles. Wikipedia also uses another license called Creative Commons Attribution Share-Alike License.

How the GFDL Started

The GFDL was first suggested in September 1999. After some changes, version 1.1 came out in March 2000. Version 1.2 was released in November 2002. The most current version, 1.3, came out in November 2008.

In December 2007, Jimmy Wales, who started Wikipedia, announced something important. The Free Software Foundation, Creative Commons, and the Wikimedia Foundation had talked a lot. They agreed on a way to change the GFDL. This change would let Wikimedia projects, like Wikipedia, also use the Creative Commons Attribution Share-Alike (CC BY-SA) license. These changes were added to version 1.3 of the GFDL. This new version allowed some GFDL materials to be used under the Creative Commons license too.

Rules for Using GFDL Material

If a document uses the current GFDL, you can use it for many things. But you must follow these rules:

• You must give credit to all the people who wrote the document before you. This is called attribution.
• You need to keep a record of all the changes you make to the document.
• If you change the document, your new version must also use the same GFDL.
• You must keep the full text of the GFDL license with the document. You also need to keep any parts that the original author said could not be changed. These are called "invariant sections."
• You cannot use special technology, like DRM, to stop people from sharing or changing the document.

Special Sections in Documents

The GFDL has a special way of looking at a "Document" and "Secondary Sections." Secondary sections are like extra parts, such as introductions or appendices. They are not part of the main document's topic. They might talk about the author's connection to the topic.

The main part of the document can be changed freely. But some secondary sections have rules. For example, you must always give credit to earlier authors. Also, some "invariant sections" chosen by the original author cannot be changed. If you change the main document, you usually have to change its title. This is unless the original authors say you can keep the same title.

The license also has rules for things like front and back covers of books. It also covers sections like "History," "Acknowledgements," "Dedications," and "Endorsements." These features were added to make the license more useful for companies that publish software documents.

Selling GFDL Documents

The GFDL says you must be able to "copy and distribute the Document in any medium, either commercially or noncommercially." This means you can sell copies of GFDL documents. The GFDL was made with commercial publishers in mind. This helps them fund free documents without losing important freedoms.

So, if a document has rules that stop people from selling it, it cannot use the GFDL. However, sometimes using a small part of a restricted document might be allowed under "fair use" laws. This means you don't need a license for that small part if it's used in a fair way.

GFDL and Creative Commons Licenses

The GFDL and Creative Commons licenses both help share content freely. But they usually don't work together directly. They are not compatible.

However, in version 1.3, a special rule was added. This rule was made because the Wikimedia Foundation asked for it. It allowed certain websites using the GFDL to also offer their work under the CC BY-SA license. This was a temporary rule. It let big websites where many people write together, like a public wiki, switch to the CC BY-SA 3.0 license. They could do this without asking every single author for permission.

For this to happen, the work had to meet a few conditions:

• The work had to be made on a "Massive Multiauthor Collaboration Site" (MMC), like Wikipedia.
• If content from outside the MMC was used, it had to be under GFDL Version 1.3 (or an earlier version that allowed later versions). It also could not have any special cover texts or invariant sections. If it wasn't from an MMC, it could only be relicensed if it was added to an MMC before November 1, 2008.

This special rule was only allowed until August 1, 2009. The FSF said that all content added to Wikipedia before November 1, 2008, met these rules. In June 2009, after a public vote, the Wikimedia Foundation decided to use this process. They started offering their content under both the GFDL and the CC BY-SA license.

How GFDL Rules Are Followed

So far, no one has gone to court over the GFDL. But its sister license for software, the GNU General Public License, has been used in court successfully.

Sometimes, content from Wikipedia has been copied by other websites, like Baidu Baike, without following the GFDL rules. But no one has ever taken these organizations to court for breaking the GFDL rules. In the case of Baidu, Wikipedia just asked them to follow the license rules and give proper credit.

Other Licenses for Free Works

• Creative Commons license
• Design Science License
• Free Art License
• FreeBSD Documentation License
• Open Content License
• Open Game License
• Open Publication License
• WTFPL

Projects Using the GFDL

• Most projects from the Wikimedia Foundation, including Wikipedia. (But not Wikivoyage and Wikinews). Since June 15, 2009, these wikis also use the Creative Commons Attribution Share-Alike license.
• An Anarchist FAQ
• Citizendium – uses GFDL for articles that came from Wikipedia.
• Free On-line Dictionary of Computing
• Last.fm – artist descriptions use GFDL.
• Marxists Internet Archive
• PlanetMath (now uses CC BY-SA license).
• Rosetta Code
• SourceWatch
• The documents that describe TRAK, which is a framework for enterprise architecture, use the GFDL.
• Abstract Algebra by Thomas W. Judson.
• The BR Bullpen on Baseball-Reference, which is a baseball wiki written by users.

See also

In Spanish: Licencia de documentación libre de GNU para niños