GNU Free Documentation License

The **GNU Free Documentation License** (GFDL) is a copyleft license for free documentation, designed by the Free Software Foundation (FSF) for the GNU Project. The GFDL allows users to freely copy, redistribute, and modify a document, provided that all copies and derivatives are available under the same license. This ensures that the documentation remains free and open for public use and modification.

History

The GFDL was released in draft form for public comment in September 1999 and officially released in March 2000. It was created to complement the GNU General Public License (GPL), which is used for software. The FSF recognized the need for a similar license for documentation, ensuring that manuals, textbooks, and other written works could be freely used and modified in the same spirit as free software.

Key Features

Copyleft

The GFDL is a copyleft license, meaning that any derivative works must be licensed under the same terms. This ensures that the freedoms to use, modify, and distribute the document are preserved in all copies and derivatives. This concept is central to the philosophy of free software and free documentation.

Invariant Sections

One unique feature of the GFDL is the concept of invariant sections. These are parts of the document that cannot be modified by future editors. Invariant sections are intended to preserve the integrity of certain parts of the document, such as a preface or a statement of authorship. However, this feature has been controversial, as it can limit the flexibility of the document.

Cover Texts

The GFDL also allows for the inclusion of cover texts, which are short passages that must be displayed on the front and back covers of the document. These texts are intended to provide important information about the document, such as its title, authors, and license. Like invariant sections, cover texts cannot be modified in derivative works.

Application and Usage

The GFDL is primarily used for software documentation, but it can be applied to any written work. It has been adopted by a variety of projects, including Wikipedia and other Wikimedia Foundation projects, which used the GFDL until transitioning to the Creative Commons Attribution-ShareAlike license in 2009.

Wikipedia and Wikimedia

The GFDL was the original license for Wikipedia and other Wikimedia projects. However, the complexity and limitations of the GFDL, particularly regarding the handling of invariant sections and cover texts, led to a community-wide vote in 2009 to transition to the Creative Commons Attribution-ShareAlike license. This transition was facilitated by a special provision in the GFDL that allowed for relicensing under certain conditions.

Software Documentation

Many free software projects use the GFDL for their documentation. This includes manuals, user guides, and other written materials that accompany software. By using the GFDL, these projects ensure that their documentation remains free and open, in line with the principles of free software.

Criticism and Controversies

The GFDL has faced criticism from various quarters. One major point of contention is the concept of invariant sections, which some argue contradicts the principles of free documentation by restricting modification. Others have criticized the complexity of the license, making it difficult for users to fully understand their rights and obligations.

Invariant Sections

The inclusion of invariant sections has been particularly controversial. Critics argue that these sections can be used to impose restrictions on the document that are inconsistent with the principles of free documentation. For example, an invariant section could contain promotional material or ideological statements that future editors are unable to remove or modify.

Complexity

The GFDL is also criticized for its complexity. The license is lengthy and contains numerous provisions that can be difficult for users to navigate. This complexity can be a barrier to adoption, particularly for smaller projects or individual authors who may not have the resources to fully understand the license.

Future of the GFDL

Despite the criticisms, the GFDL remains an important license for free documentation. The FSF continues to support and promote the GFDL, and it is still widely used in the free software community. However, the rise of alternative licenses, such as the Creative Commons licenses, has provided users with more options for licensing their works.

Alternatives

The Creative Commons licenses, particularly the Attribution-ShareAlike license, have become popular alternatives to the GFDL. These licenses offer similar freedoms but are often simpler and more flexible. The transition of Wikipedia and other Wikimedia projects to Creative Commons licenses is a notable example of this trend.

Ongoing Development

The FSF continues to develop and refine the GFDL. While there have been no major revisions since its initial release, the FSF has issued clarifications and guidance to help users understand and apply the license. The ongoing development of the GFDL reflects the evolving needs of the free documentation community.