Creative Commons, the non-profit whose ubiquitous licenses disseminate open material, offers a number of licenses with a range of options for sharing open projects. The most permissive, “the ones,” it says, “that can be most readily used, shared, and remixed by others, and go furthest toward creating a commons of freely reusable materials,” are labeled (borrowing standards set by Freedom Defined, a collaborative network of “free culture advocates and researchers”) as “Approved for Free Cultural Work.” According to Freedom Defined’s “Definition of Free Cultural Works,” the standard adopted by the Wikimedia Foundation (Wikipedia’s parent), a free license should satisfy four criteria: 1) “The freedom to use and perform the work”; 2) “The freedom to study the work and apply the information”; 3) “The freedom to redistribute copies”; and 4) “The freedom to distribute derivative works.” The only two Creative Commons licenses capable of permitting “Free Cultural Work,” it therefore proclaims, are CC-BY (Creative Commons Attribution) and CC-BY-SA (Creative Commons Attribution ShareAlike).The Open Knowledge Foundation’s Open Definition likewise explains that “A piece of data or content is open if anyone is free to use, reuse, and redistribute it — subject only, at most, to the requirement to attribute and/or share-alike.” It therefore also lists CC-BYand CC-BY-SA as the only two “open” Creative Commons licenses.
But why not formally bar the commercial use of materials with the non-commercial use only (-NC) licensing option? Freedom Defined argues that -NC is too vague and expansive and too easily bars a range of legitimate uses. It also points out that the Open Source Definition and other open standards “explicitly state that sale and other commercial uses must be allowed for a license to be considered free.”Creative Commons follows these recommendations. It distinguishes between “free” and “non-free” licenses, and, according to its standards, the restriction on commercial use pushes the license from “free” to “non-free.” The organization explains that Creative Commons “exists not just to create copyright licenses, but also to encourage the creation of a thriving commons through sharing knowledge.”Freedom Defined argues that “The moment you choose any Creative Commons license, you choose to give away your work.”Another reason, however, for not explicitly preventing the commercial exploitation of an otherwise free resource with a –NC option is that, according to the terms of a CC-BY-SA license itself, you don’t really have to. Under the Share-alike (-SA) option all derivative works must be licensed upon the same terms as the original. Any project deriving work must be shared on equal terms. Even without the clause, specific parts of a larger project derived from a CC-BY license must still be shared freely.