CZ:License Essays/Anthony Argyriou
The license question is a tough one, but I think the answer is CC-BY-NC-SA. I have some prejudice against the GFDL both for its own sake and because Wikipedia uses it. However, I will try to set aside that prejudice as I evaluate the options.
Firstly, the license chosen should be an established and persistent license, preferrably one supported by a foundation outside Citizendium. We shouldn't write our own license because we can't really afford to do it right. For the sort of work which Citizendium is, with the provision that some form of open license is desirable, that pretty much leaves us with various GNU project licenses, and the Creative Commons licenses. Most other licenses either aren't very good for our purposees, or are too vague. The GFDL isn't the only GNU project license we could use - the GPL and LGPL are available. Creative Commons also offers us a variety of choices, including options not available in the GNU world.
Secondly, the license chosen should not endanger Citizendium. None of the GNU or CC licenses pose direct legal threats to Citizendium, but the GFDL does pose an indirect threat to Citizendium - that we might become merely a feeder-wiki for Wikipedia. That is a direct existential threat to Citizendium. Many of the contributors here have left or scaled back their involvement at Wikipedia for good reasons, which won't be fixed by Wikipedia copying Citizendium content to improve their articles. If Citizendium becomes a feeder for Wikipedia, the goals which motivate many contributors will not be well-served, and there will be a slow drift away from Citizendium - both back to Wikipedia, and out of free-content encyclopedia-building altogether. Notice that the GPL and LGPL, which aren't ideal for the sort of content we host, are potentially incompatible with the GFDL, and using those will probably prevent Citizendium from becoming a feeder-wiki for Wikipedia. So will any CC license.
Thirdly, the license should actively help advance Citizendium's goals and plans. Citizendium plans to obtain support from educational institutions and funding groups to obtain funds and to help maintain a high quality of articles. Many of these institutions will prefer that they not be contributing to a commercial enterprise. While Citizendium is not a commercial enterprise, a license which permits commercial re-use could be seen as furthering commercial enterprises. Additionally, holders of copyright on useful material - photos and text - may be willing to release their works to Citizendium provided that the use of the work remains non-commercial. This will potentially allow us to have access to content which is not available to Wikipedia, furthering our goal of creating a better encyclopedia. Both of these points can be verified empirically, and if people involved in fundraising or licensing issues believe this is not an issue, I'd be happy to defer to them on the usefulness of an NC provision in the license.
While in general, I'm all in favor of commercial enterprise, I don't much like the idea of other people who haven't contributed being able to profit from the work of those who have. I also believe that non-commercial enterprises definitely have a place in society. I'm willing to work for Citizendium unpaid because it's a non-commercial enterprise.
The GNU project endorses use of CC-BY-SA, saying This is a copyleft free license that is good for artistic and entertainment works, and educational works. The GNU project will not endorse the NC variant, because they do not believe in restrictions based on the commercial status of the licensee. However, we do not need to be bound to their prejudices, because we're trying to do something different than the GNU project is trying to do. Ultimately, I think that the best choice of license is CC-BY-SA-NC, unless in the opinion of people running the project, the NC will do more harm than good. As I understand it, either license allows people to quote our articles extensively, provided they give a backlink or an attribution; while preventing both Wikipedia parasitizing Citizendium, and preventing the creation of ugly Citizendium mirrors the way About.com and others are parasitizing Wikipedia for their own profit.