CC's own FAQ addresses the reasons, which I find satisfactory, so I'm just going to reproduce it here and expand on the key points:
Unlike software-specific licenses, CC licenses do not contain specific terms about the distribution of source code, which is often important to ensuring the free reuse and modifiability of software. Many software licenses ...
CC BY-ND 4.0 says in section 2(a)(4):
Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You ...
Short answer: because the CC licenses have not been designed for software and source code.
This is answered by Creative Commons themselves in their FAQ:
Unlike software-specific licenses, CC licenses do not contain specific
terms about the distribution of source code, which is often important
to ensuring the free reuse and modifiability of software. ...
Yes, they can publish a PDF without publishing the modified LaTeX sources. No, this is not DRM.
CC-BY-SA is not an open-source license. It is intended for creative works such as photographs or writings even where there might not be any kind of editable source format.
The license explicitly allows any licensee to change the format of the work:
You can use all the text, and most of the images, under some conditions, and those conditions include proper attribution.
Wikipedias text is under the Creative Commons Attribution-Share Alike 3.0 license (CC BY-SA 3.0). If you abide by those conditions - that is, credit the writers, and publish the text (or whatever adaptations you've made to the text) ...
Company A violated the license by redistributing in a manner they were not licensed to do so when they changed from CC X to CC Y.
Company B thought they were doing a permitted thing by taking what turned out to be incorrectly / illegally licensed, but thought doesn't count, so they have no right to redistribute and so they too would be in violation of ...
The CC-BY-SA 3.0 license is “forward compatible” with later versions. In section 4(b):
You may Distribute or Publicly Perform an Adaptation only under the terms of:
(i) this License;
(ii) a later version of this License with the same License Elements as this License;
(iii) a Creative Commons jurisdiction license (either this or a later license ...
Sparr's original answer was good, but he should have left in the bit about being sued.
The point is that the language used in CC0 constitutes a legal hazard for anyone that receives a program under CC0 and uses it in good faith.
This is the infamous patent clause of CC0:
No trademark or patent rights held by Affirmer are waived, abandoned, surrendered, ...
The Creative Commons organization has a page on Legal Music For Videos which states (emphasis mine):
Under CC licenses, synching the music to images amounts to transforming the music, so you can’t legally use a song under a CC No Derivative Works license in your video.
This corresponds to the "synchronization" provision in section 1(a) of CC-BY-SA 3.0 (...
Well, this gets complicated and legal. (Caveat: I am not a lawyer.) According to Creative Commons, their licenses:
give everyone from individual creators to large companies and institutions a simple, standardized way to grant copyright permissions to their creative work.
In short, CC licenses apply to creative works and are meant to relax or waive the ...
Company A is certainly liable for their misrepresentation of licensing terms. However, that does not legally excuse Company B's downstream distribution under those wrong terms; they have (accidentally) committed copyright infringement as well.
In the United States, copyright infringement is a strict liability tort, meaning that Company B's ignorance and ...
CC-BY-SA is a technically perfect open source license.
CC-BY-SA's use is discouraged because of the "license proliferation" problem.
Going into more detail on the first point, first we need to know what it means to be an "open source" license. OSI has a great definition of what it means to be open: http://opensource.org/osd
Lets go through each ...
In 4(c) of CC BY-SA 3.0 it is defined how attribution has to be provided. For the work’s URL, it says:
[…] (iii) to the extent reasonably practicable, the URI, if any, that Licensor specifies to be associated with the Work, unless such URI does not refer to the copyright notice or licensing information for the Work; […]
if a work’s page no longer ...
You only need to share the image under CC-BY-SA. This means your project will be multi-licensed.
The important part is that only the image is currently under BY-SA. Since the only requirement of the license is that if you share, modify or redistribute the image, you have to license it under BY-SA. The license of the image can have no bearing on the rest of ...
In the large majority of cases, the software of a program and the artwork used by a program are not related to each other where copyright is concerned.
An exception might be an image that was created by a program from a fixed formula and the source code of that program.
For a work to be considered a derived work, there must be a way to go from the original ...
I do not think this is a question that has a straightforward yes or no answer.
The CC NC clause is really hard to get a grasp on, and Creative Commons do not provide much guidance about it. Their FAQ: Does my use violate the NonCommercial clause of the licenses is deliberately vague, and can be summed up in this sentence:
Whether a use is commercial will ...
No, it’s not allowed.
It says on the license summary page:
No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
And in the license:
For Licensed Material (i.e., the unmodified work):
No downstream restrictions. You may not offer or impose any ...
No, CC-BY-ND isn't Open Source. It violates rule 3 of the Open Source Definition:
The license must allow modifications and derived works, and must allow
them to be distributed under the same terms as the license of the
It also violates the freedom 3 of the Free Software Definition:
The freedom to ...
Suppose that I patent an algorithm, X. Then I develop and release an implementation of that algorithm, Y. I release Y with an open source license, granting permission for others to use and distribute Y. Generally speaking, it has always been assumed that my granting of permission to use and distribute Y has also been a grant to use and distribute X. However, ...
Your analysis seems to be sound except:
You may be able get around this by
Referring to the CC media rather than including it (downloaded from the web)
Publishing a link (inside the app) to the CC media in an approved non-drm mechanism.
Including the CC media in a form that is unprotected.
Note: You CAN use DRM, you just cannot restrict the rights.
You can license your intellectual property under different licenses to different people. But when your license follows the definitions of open source and/or free software, the licensees have the right to relicense it under the same terms to other people. So this would not be an effective way to control distribution.
When you want to control distribution, ...
Bob can relicense it under any license he wishes.
Taking credit for Alice's work is another thing. In jurisdictions that hold up moral rights, Bob can't. The moral rights cannot be given up by Alice, so they are still intact. What consists moral rights differs a bit, but proper attribution is usually included. In jurisdictions without moral rights, ...
The code you're building on in BY-NC-ND, which requires attribution, forbids commercial use, and disallowed derivatives.
If you build on that code, it's a derivative, which is not allowed by the license. Even if you gradually replace everything, it is still a derivative.
Anything you change you can call your own, but the resulting work will always be a ...
This interpretation is correct.
The share-alike clause in other licenses is only relevant to contributions made by others than the original licensor. In fact, the CC-BY-NC 4.0 license does not grant you the right to sub-license the original work at all, as shown in section 2(a)(1) (emphasis mine):
Subject to the terms and conditions of this Public ...
One of the problems with CC NC is that when you say "I am not sure what "Commercial purposes" are", you are not alone in that.
The relevant clause in CC BY-NC 3.0 reads
You may not exercise any of the rights granted to You in Section 3 above in any manner that is primarily intended for or directed toward commercial advantage or private monetary ...
Unless I've completely misunderstood the question, that would be violating two of the Creative Commons license's restrictions:
That it can only be used in non-commercial contexts
That any derivative works be licensed under the same license
I really don't know how you thought you could use CharacterController2D in a commercial closed-source app! That's the ...
Warning: It seems that this isn’t possible, because the provision (that only "the last license applied" has to be followed) was introduced with CC BY-SA 4.0, so CC BY-SA 3.0 doesn’t allow it. Please see Trevor’s answer.
If you adapt¹ content licensed under CC BY-SA 3.0, you can (additionally) license your contribution under GPLv3 (but not the other way ...
Let's go through section 3(a) of the license bit by bit.
If You Share the Licensed Material (including in modified form), You must:
A. retain the following if it is supplied by the Licensor with the Licensed Material:
identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any ...
No. Any modifications you apply that aren't sanctioned by the owner are classed as derivative works. Your result still contains the author's material, true, but you've changed the way it's presented - it's like removing some code that's just a wrapper for a routine. You're changing the product, which creates a derivative work, which is disallowed.
tl;dr: No ...