Is Stack Exchange allowed to unilaterally change previously published content license? The original thread can be found here: Stack Exchange and Stack Overflow are moving to CC BY-SA 4.0 As far as I understand, Stack Exchange can move on to CC BY-SA 4.0 for content published in the future, but they are not allowed to unilaterally change the license of previous publications. Several threads have been created requesting answers regarding this issue from Stack Exchange, however, the only answer from moderator did not give any meaningful explanation. Since this is a legal issue, I would like to ask of Law Stack Exchange community to give expert opinion on this matter. Can Stack Exchange change the license for previously published content without the consent of users?
What SE can do is controlled primarily by the Terms of Service. What most matters is the section on Subscriber Content, which says: You agree that any and all content, including without limitation any and all text, graphics, logos, tools, photographs, images, illustrations, software or source code, audio and video, animations, and product feedback (collectively, “Content”) that you provide to the public Network (collectively, “Subscriber Content”), is perpetually and irrevocably licensed to Stack Overflow on a worldwide, royalty-free, non-exclusive basis pursuant to Creative Commons licensing terms (CC-BY-SA), and you grant Stack Overflow the perpetual and irrevocable right and license to access, use, process, copy, distribute, export, display and to commercially exploit such Subscriber Content, even if such Subscriber Content has been contributed and subsequently removed by you... This means that you cannot revoke permission for Stack Overflow to publish, distribute, store and use such content and to allow others to have derivative rights to publish, distribute, store and use such content. The CC-BY-SA Creative Commons license terms are explained in further detail by Creative Commons, but you should be aware that all Public Content you contribute is available for public copy and redistribution, and all such Public Content must have appropriate attribution. This part has not changed: the purported license is still "CC-BY-SA", and the TOS does not explicitly specify a version. What apparently has changed in the relevant section is one "helpful information" link, which now points to https://creativecommons.org/licenses/by-sa/4.0/. So the interesting question arises whether that would constitute an unpermitted post-hoc change in the terms by which SE has license to my older stuff. This matter came up in a reviled Meta question; as I pointed out, the TOS also included a merger clause that This Agreement (including the Privacy Policy), as modified from time to time, constitutes the entire agreement between You, the Network and Stack Exchange with respect to the subject matter hereof. This Agreement replaces all prior or contemporaneous understandings or agreements, written or oral, regarding the subject matter hereof. Because of that, the TOS is self-contained and stuff found on other web pages are not part of the agreement. This in itself is a bit of a problem because you can't both say "we're not bound by stuff outside of this page" and say "the specific terms of the license are outside this page". That particular clause is gone, but there is an analog in the current TOS: These Public Network Terms represent the entire agreement between you and Stack Overflow and supersede all prior or contemporaneous oral or written communications, proposals, and representations with respect to the public Network or Services or Products contemplated hereunder. Furthermore, the TOS contains the following "we can change it" clause: Stack Overflow reserves the right, in its sole discretion, to modify or replace these Public Network Terms, as our business evolves over time and to better provide Services and Products to the Stack Overflow community, or to change, suspend, or discontinue the public Network and/or any Services or Products at any time by posting a notice on the public Network or by sending you notice via e-mail or by another appropriate means of electronic communication. I assume but do not know for a fact that a similar clause existed in prior versions of the TOS. So I conclude that the change is legal.
To the extent that Admin is running a business rather than a free relay server, Admin will have various legal concerns. As I understand the system as you describe it, a user uploads some content to a machine, operated by AMastodonAdmin, which then makes that content available to others. W.r.t. US law, the admin needs to be concerned with a number of things. Copyright violation is one: he may get sued for contributory infringement. The DMCA safe harbor provision reduce the risk, if complied with. Defamation is another potential issue (a publisher is liable for damages under defamation law, as well as the author). &quot;Section 230&quot; may provide protection, but there is a large body of case law mentioned in there that would heave to be taken into consideration – and two upcoming Supreme Court cases. (Basically, Section 230 says that &quot;No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider&quot;). The administrator has a property right to include / exclude anyone they want to, on their machine, except that a contract between Admin and User might limit his right. A TOS is a contract, which typically says &quot;You can use my machine in a specific way as long as you follow these rules&quot;. Requiring payment in exchange for access limits Admin's right to do whatever they want. For free-access systems, there is typically a clause saying &quot;we can kick you off if we want&quot;, though also implying that they will only kick you off for a specific action (&quot;violating community standards&quot;). In order to legally receive content from User, you need permission from User to redistribute their intellectual property (therefore a TOS is virtually mandatory). This would include a warranty from User that they have the right to upload whatever they do upload, granting a correct license to Admin (read the Stack Exchange TOS), and while you are at it, you should say explicitly that if a user misbehaves, they can be banned. Silence is legally problematic, compared to explicit permission or prohibition, because then there may be a long legal wrangle over whether lack of prohibition is implicit permission. Admin technically should care about GDPR, though enforcement may make this a non-issue. A US company operating as Admin would have a real concern with GDPR, but a guy running a free basement server, having no ties to the EU, might ignore GDPR, the same way they might ignore some other nation's law against apostacy.
australia Assignment and licencing of Copyright is dealt with in s196 of the Copyright Act 1968. Copyright is personal property and, subject to this section, is transmissible by assignment, by will and by devolution by operation of law. Whether someone can renounce ownership of personal property under Australian law is not entirely clear. It appears that the answer is probably yes if the owner forms the intention to abandon it. However, that does not make it public domain and the copyright might be able to be claimed by the "finder" of the abandoned property. There appears to be no provision in the law for "destroying" the personal property that is copyright. Unlike, say, a car, it is not physically possible to destroy copyright. Notwithstanding, a copyright owner who purports to disclaim copyright has probably granted a permissive, royalty-free, non-revocable, non-revocable, perpetual licence to everyone and this would bind their successors in the copyright which is practically no different from a work that is public domain. Even if this were not the case, the copyright owner would almost certainly be estopped from enforcing copyright against anyone who had taken up their offer of "public domain".
The CC-ND license seems to be what you are looking for. However, Sec. 2(a) has two conditions, one allowing copying and distribution of the unmodified original (as stated in A), but also allows the user to modify but not distribute a modified version of the work (they may "produce and reproduce, but not Share, Adapted Material"). This would mean that a reader could rewrite your paper, as long as they keep it to themselves. If this bothers you, I think you could not rely on a standard named license, instead you'd have to provide your own – such as CC-ND 4.0 without clause (2)(a)(B). Rewriting a legal document is a risky proposition, even for a legal professional, because you have to carefully think through all of the implications of any new punctuation, adjectives, and deletions. If you contemplate deleting clause (2)(a)(B), you should come up with a line of reasoning that compels you do delete it in order to accomplish your goal, and check that the deletion doesn't thwart that goal. That is why people pay money to lawyers (and also why you need to make your goal clear to that lawyer, lest the agreement be inconsistent with your goal).
Choice 2 is what the writers of the license have in mind. You own the physical media on which the copy is delivered, such as a DVD or floppy disk (if there was physical media). But you do not own the copy of the software, you merely have purchased a license to use it, which may be revocable under specified circumstances. This is different from the law in the case of a book. Why you buy a book, you own a copy of the book, although you do not own the copyright to the book, and may not make additional copies. The license model was adopted by commercial software distributors for several reasons, but largely to avoid the "first sale doctrine". When you buy a copy of a copyrighted work, you have the right (under US law at least) to lend, rent, sell, or give-away that copy. You do not need the permission of the copyright holder to do any of these. Those in the commercial software business did not want customers to be able to do those things legally. By making the software subject to a license, which is a contract, they could write that license to restrict or prohibit those rights. Sellers also wanted to prohibit reverse engineering of the software, and to restrict use of the software. (For example, to limit the user to installing it on a single computer.) There was at first much dispute over the enforcability of such license agreements. But most US courts now accept them as valid and enforceable, and copyright law has been modified to take account of them. Specifically, 17 USC 109 (2)(b)(1)(A) seems to include a legislative acceptance of this rule.
You will need a license for any library that you are including in your product. Including libraries that you didn't really want to include, but which are needed by another library that you intentially include. And you will have to agree to all the licenses simultaneously, which may be difficult. If several libraries have conflicting licenses (that is you cannot possibly respect A's and B's license at the same time), then you must remove one of the libraries until no conflicts are left.
Use of SE is subject to the terms and conditions specified here. Section 3 says "You agree that all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license." That means that your contributions can be used forever. That means the stuff is there, end of story. Section 11 on Termination says "Stack Exchange may also terminate, block, or suspend any and all Services and access to the Network immediately, without prior notice or liability, in its sole discretion, for any reason or no reason at all, including but not limited to any Subscriber breaches of any of the terms or conditions of this Agreement". That means you can be banned. So, yes, what they did is legal.
This is not (necessarily) copyright violation It's possible that Quora's usage falls within Fair Use. At the very least, the argument could be made. If it does, then there is nothing that Stack Exchange or the OP can do. Stack Exchange can choose not to protect their copyright Unlike trademarks, which lapse if not protected, copyright endures. Therefore Stack Exchange can pick and choose the copyright fights they want to get involved in and those they don't. If you have brought it to the attention of the copyright owner (or, in this case, licensee) and the copyright owner chooses not to act then you have done all you can and significantly more than you have to do. The OP has copyright I note that one of the examples is your question. As the copyright holder, you are free to issue a DCMA takedown notice on Quora if you feel your copyright has been violated.