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	Current version': November 3, 2008
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 just GFDL) is a special set of rules for sharing information. It's like a permission slip that lets people copy, share, and even change documents. This license was created by the Free Software Foundation (FSF) for the GNU Project.

The main idea behind GFDL is copyleft. This means that if you use a document under GFDL, any new versions or copies you make must also be available under the same GFDL rules. This helps keep information free for everyone to use and improve.

GFDL was first made for things like instruction manuals, textbooks, and other helpful guides that come with computer programs. But it can be used for any kind of written work. For example, the online encyclopedia Wikipedia used GFDL for most of its articles for a long time.

How the GFDL License Started

The GFDL license was first shown to the public in September 1999 so people could give their ideas. After some changes, the first official version (1.1) came out in March 2000. Later, versions 1.2 (November 2002) and 1.3 (November 2008) were released. Version 1.3 is the one used today.

In 2007, Jimmy Wales, who started Wikipedia, announced an important change. The Free Software Foundation and Creative Commons (another group that makes free licenses) worked together. They wanted to make it possible for projects like Wikipedia to also use a similar license called Creative Commons Attribution Share-Alike (CC BY-SA).

This change was added to version 1.3 of the GFDL. It allows some materials that use GFDL to also be used under the Creative Commons Attribution Share-Alike license. This made it easier for different free content projects to work together.

What You Can Do with GFDL Material

If a document uses the GFDL license, you can use it for almost any reason. But you must follow certain rules:

• Give Credit: You must say who the original authors of the work were.
• Track Changes: If you change the work, you need to keep a record of those changes.
• Same License: Any new work you create based on the GFDL document must also use the GFDL license.
• Keep the Rules: You must include the full text of the GFDL license with your copies. You also need to keep any special sections the original author said couldn't be changed, and any copyright notices.
• Stay Open: You cannot use special technology (like DRM) to stop people from copying or changing the document.

Special Sections in Documents

The GFDL license talks about "Secondary Sections." These are parts of a document that might be at the beginning or end, like an introduction or an appendix. They can explain the author's connection to the topic, but they don't contain the main information of the document itself.

While the main part of the document can be changed freely, some of these secondary sections might have rules about how they are used. For example, some parts might be "invariant sections," meaning they cannot be changed at all. If you change the main document, you usually need to change its title too, unless the original authors say it's okay to keep it.

The license also has rules for things like cover texts for books, and sections for "History," "Acknowledgements," "Dedications," and "Endorsements." These features were added to make the license more useful for companies that publish software manuals.

Selling GFDL Material

The GFDL allows you to copy and share documents in any way, whether you sell them or give them away for free. This means you can't use GFDL if you want to stop people from selling your work. The GFDL was actually designed to help commercial publishers fund free documentation.

However, if you include material that has other restrictions (like "no commercial use"), it might not be compatible with GFDL. But sometimes, using small parts of such material might be allowed under "fair use" rules in copyright law.

Working with Creative Commons Licenses

Even though GFDL and Creative Commons Attribution-ShareAlike (CC BY-SA) are both "copyleft" licenses, they are not directly compatible. This means you usually can't mix content from one license with the other without special permission.

However, because the Wikimedia Foundation (the group behind Wikipedia) asked for it, version 1.3 of the GFDL added a special, temporary rule. This rule allowed certain websites using GFDL to also offer their work under the CC BY-SA license. This was important for big projects like Wikipedia, which have many authors.

This special rule let projects like Wikipedia change their content to also be under the CC BY-SA 3.0 license. This happened in June 2009 after a public vote. This way, Wikipedia content became available under both GFDL and CC BY-SA.

How the GFDL License is Used in Real Life

So far, no one has gone to court specifically over the GFDL license. However, a similar license for software, the GNU General Public License, has been successfully used in court.

Sometimes, other websites have copied content from Wikipedia without following the GFDL rules, like Baidu Baike. Even though this happened, Wikipedia contributors haven't taken these organizations to court. Instead, Wikipedia representatives usually ask them to follow the license rules and give proper credit.

Other Ways to Share Free Works

Besides GFDL, there are other licenses that let you share content freely:

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

Projects Using the GFDL

Many projects have used the GFDL license to share their content. Here are a few examples:

• Most projects from the Wikimedia Foundation, like Wikipedia (though many now also use CC BY-SA).
• An Anarchist FAQ
• Citizendium – for articles that originally 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, a framework for enterprise architecture.
• Abstract Algebra by Thomas W. Judson.
• The Baseball-Reference's BR Bullpen, a baseball wiki.

See also

In Spanish: Licencia de documentación libre de GNU para niños