Larry Sanger has a question about Citizendium:
Suppose we grow to Wikipedian size. This is possible, however probable you think it might be.
Suppose, also, that, because we are of that size, we have the participation of a sizable portion of all the leading intellectuals of the world, in every field–and so, there are hundreds of thousands, if not millions, of approved articles. These are all long, complete with many links, bibliography, etc., etc.–all the subpage stuff. It’s reference utopia. Far better than Wikipedia has any hope of becoming.
Here’s the question, then. If we use a license that permits commercial reuse–CC-by-sa or GFDL–then every major media company in the world could, and probably would, use CZ content. Do you favor a license that allows CBS, Fox, the New York Times, English tabloids, Chinese propaganda sheets, Yahoo!, Google, and all sorts of giant new media companies to come, to use our content? Without compensation?
That's the question that Linus faced over a decade ago when he decided to adopt the GNU GPL instead of the earlier one that forbade any kind of money changing hands. And as Linus has said many times, choosing the GNU GPL was one of the best decisions he ever made, because it has widened support for Linux enormously, and as a result has driven its development even faster.
There's your answer, Larry....