copyrightable creative component. This may indeed occur in biodiversity where data are formatted as software-generated “species pages”.
This is, however, not the primary concern with NC-licensed software. The creator of such work created using NC-licensed software may have full ownership and copyright to it, but is limited by the contractual obligations which arise from using the NC license. The critical question is perhaps: Which level of diligence in preventing commercial use of such works or data sets is required? Is it sufficient that no commercial use was intended at the time of creation (but may the work later be sold)? May the author give it as a present to a third party, which may then put it to commercial use? Or is the author required to prevent this from happening for all times, including binding future copyright heirs?
Following the recommendations of Creative Commons, we advise that the only Creative Commons license suitable for software is the CC0 rights release license. Dedicated software licenses should be used in all other cases.
License compatibility
Works licensed under CC licenses that do not include the NC condition are naturally available for non-commercial use. However, a common misconception is that such works and those licensed with an NC condition can always be mixed in a derivative work, creating a new work under the more restrictive license.
While it is possible, e.g., to combine works licensed under CC BY-NC with works licensed under CC BY content, it is not possible to do so with works under licenses containing the Share Alike condition (e.g., the CC BY-SA license on Wikipedia text and most images). Share Alike prevents the use of a work under a more restrictive license – specifically in this case under an NC license. A derived work that combines NC-SA and other licenses must be shared under an NC license. This would be incompatible with the Share Alike license terms for an included CC BY-SA work (Katz 2006). License compatibility can be checked, e.g., with the Creative Commons Licenses Compatibility Wizard (Creative Commons Taiwan 2011).
The problem of license incompatibility may also arise when licensors, recognizing the problems with the CC NC license, amend it with their own definitions (see, e.g., Massachusetts Institute of Technology 2011, Smith 2011, or examples given in Keller and Mossink 2008). In the case of the CC BY-NC-SA license, if two licensors annotate a license in contradictory ways, these two licenses may be incompatible with each other (while each may remain compatible with unmodified and unspecified CC BY-NC-SA licenses).
License incompatibility problems also surface in relation to license models outside Creative Commons. Only the CC BY and CC BY-SA licenses (but not CC BY-ND, CC BY-NC, or CC BY-NC-SA) meet the criteria of openness that are used to determine compatibility with, e.g., software licenses laid out in each of:
