Wikivoyage:Why Wikivoyage isn't GFDL
Some open content Wiki sites use the GNU Free Documentation License for their work. For Wikivoyage, this license doesn't meet our goals, so we've chosen a different one instead. This page tries to explain why.
The GFDL was developed to support making Free Content versions of software manuals, textbooks, and other large references. It has some heavy requirements for what you have to distribute with a document under the GFDL. For example, you have to include a copy of the GFDL, a changelog, as well as "transparent" (i.e. source) versions if you distribute over 100 copies.
These requirements aren't really all that onerous for large volumes of text. But for Wikivoyage, we really want to have each article redistributable on its own. Wikivoyage articles can be as small as 1-2 printed pages. For such small documents, it just doesn't make sense to require people to pass out another 10 pages of legalese text, as well as floppy disks or CDs full of Wiki markup.
Consider these small "publishers" who would distribute stacks of photocopied printouts of Wikivoyage articles:
- Local tourist offices
- Hotels or guesthouses
- Helpful travellers
- Exchange student programs
- Wedding or event planners
Burdening these publishers with restrictions meant for software documentation or textbooks would mean that they'd either ignore our license—a bad precedent to set—or, more likely, just not use our work.
We make our content Free so we can collaborate on this wiki, but also because we want it to be seen and used. We can't serve travellers with useful information if they can't get to that information in the first place.
A lightweight alternative 
The license we've chosen, the Creative Commons Attribution-ShareAlike 3.0, is much easier and more lightweight. We think that using the Attribution-ShareAlike 3.0 license (by-sa) meets our goal of having copyleft protection on Wikivoyage content, without putting an excessive burden on small publishers. All that needs to be included are copyright notices, author attribution, and the URL of the license; this can be done in a short paragraph at the end of the article.
Dual licensing 
In the past, before GFDL and CC BY-SA became mutually compatible, some Wikivoyager's chose to dual license their work under both the CC BY-SA and the GFDL. However, now that these licenses have been updated to be mutually compatible with each other, dual licensing is no longer important.