Does my use violate the NonCommercial clause of the licenses?
CC's NonCommercial (NC) licenses prohibit uses that are "primarily intended for or directed toward commercial advantage or monetary compensation." This is intended to capture the intention of the NC-using community without placing detailed restrictions that are either too broad or too narrow. Please note that CC's definition does not turn on the type of user: if you are a nonprofit or charitable organization, your use of an NC-licensed work could still run afoul of the NC restriction, and if you are a for-profit entity, your use of an NC-licensed work does not necessarily mean you have violated the term. Whether a use is commercial will depend on the specifics of the situation and the intentions of the user.
In CC's experience, it is usually relatively easy to determine whether a use is permitted, and known conflicts are relatively few considering the popularity of the NC licenses. However, there will always be uses that are challenging to categorize as commercial or noncommercial. CC cannot advise you on what is and is not commercial use. If you are unsure, you should either contact the rights holder for clarification, or search for works that permit commercial uses.
CC has a brief guide to interpretation of the NC license that goes into more detail about the meaning of the NC license and some key points to pay attention to. Additionally, in 2008, Creative Commons published results from a survey on meanings of commercial and noncommercial use generally. Note that the results of the study are not intended to serve as CC's official interpretation of what is and is not commercial use under our licenses, and the results should not be relied upon as such.

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