Does the exact spelling matter when referencing the CC BY-SA licence? We have been having a discussion in a chat room on whether the exact spelling matters when referring to a License, in this particular case the CC BY-SA License - which applies to any content posted to any of the Stack Exchange sites - and is linked to in the Stack Exchange Network Terms of Service I had mistakenly referred to it (in a comment) using the name CC-by-SA instead of the correct CC BY-SA (additional hyphen and lower case by). It was pointed out to me that this incorrect usage could potentially jeopardise any legal case brought against Stack Exchange in the US. Is this the case? Would an unintended misspelling be that serious in a legal case? Would the fact that the misspelling occurred in a transient comment make any difference? Would the fact that I am an elected moderator (on SU) - and therefore presumably a &quot;representative&quot; of Stack Exchange - make any difference? (Compared to and ordinary user making the same mistake). Note that the Moderator Agreement explicitly states &quot;I acknowledge and agree that I am an independent volunteer moderator to Stack Overflow and I am not an employee, agent or representative of Stack Exchange Inc., and I have no authority to bind Stack Exchange Inc. in any manner.&quot;
The only potential problem would be if CC-BY-SA and CC BY-SA (and other variants) come to refer to two different things. There is a problem that in any spelling, "cc by sa" is informal shorthand for a class of licenses. One of them is here: it looks to me like they "officially" call it the Creative Commons Attribution-ShareAlike 2.0 license. Here is another version. The existing practice of referring to CC licenses is very problematic, because there are multiple versions, and without a link to the specific version, a person can't know what they are being bound by. This is an example of a real ambiguity. There is (at least presently) no difference between CC-BY-SA, CC by-SA, or any other variants. CC-BY and CC-SA, on the other hand refer to different things. Problems only arise when it's not possible to objectively figure out what a licensor was referring to.
Reviewing https://stackexchange.com/legal/trademark-guidance shows the following: The logos associated with Stack Exchange Inc. and any Stack Exchange site are a trademark. The purpose of trademark law is to prevent consumers from being misled as to the origin of a product. So if you were making a product, and you used a Stack Exchange name or logo in your product (or in its advertising) in such a way that would mislead someone into thinking that your product was owned by, operated by, endorsed by, or in any way part of Stack Exchange Inc., you would be violating the trademark and this would not be legal. Our logo images and site names are copyrighted. Any content on the Stack Exchange Network not contributed by users is copyrighted. Copyright is different than trademark. Ordinarily you couldn't copy it. But if you were writing a news story or blog post about a Stack Exchange site, reproducing the logo image would almost certainly be considered &quot;fair use&quot; and allowed under trademark law because you were not using it &quot;in trade.&quot; So the answer to your question is yes, you would need to seek the permission of the trademark holder.
There isn't a meaningful difference; they just renamed it for version 2.0. Comparing CC-BY-ND-NC 1.0 and CC-BY-NC-ND 2.0 side-by-side, one can easily see that their scope is the same--there is some rewording, but that rewording is common to all CC-1.0 vs. CC-2.0 licenses, and not indicative of any change in the fundamental scope or purpose of CC-BY-ND-NC vs. CC-BY-NC-ND.
Your issue is trademark, not copyright. If these other guys use their mark (product name) in commerce but did not register it, they have an unregistered trademark which you could be infringing. Between two users of the same trademark, the first to use in commerce wins. (There is a territorial component but with the Internet, meh.) If the trademark is registered that gives them a presumption of validity. Trademark infringement is concerned with consumer confusion. If someone uses someone else's trademark in a way that confuses consumers as to the origin of the goods, that's a problem. What this means is that if I make tires with the name Sportie and someone else makes soap also with that name Sportie there is not a high likelihood of confusion. Likewise a hotel in Washington called Runner's Cove probably doesn't infringe a shoe store in Florida with the same name. Fantasy games and fantasy books sold over the Internet? Sounds like a potential problem that you might want to clear up before the second book.
It's possible that CAD has a separate licence from the authors of ABC that allows them to produce a closed source copy. If not, they have no right to distribute CAD. However two wrongs don't make a right, and so you don't get to violate the copyright of CAD.* Unfortunately, unless you are one of the authors of ABC, you have no standing to sue the authors of CAD. You can only notify the authors of ABC and hope they do. If the authors of ABC don't have the resources to pursue the matter, you may be out of luck. That's one of the reasons the FSF gets copyright assignments for their projects. * It turns out that this is a much more debateable issue than I first thought. Some courts have held that an unauthorized derivative work is not copyrightable.
I can see two points you might be confused about in your question. 1. Works can be in the public domain without having a CC license The Wikipedia statement and the government statement are not inconsistent with each other; just because something isn't available under a Creative Commons license doesn't necessarily mean that it is restricted by copyright. In fact, CC licenses are moot for material in the public domain: When a work is in the public domain, it is free for use by anyone for any purpose without restriction under copyright law. Public domain is the purest form of open/free, since no one owns or controls the material in any way. ... Creative Commons licenses do not affect the status of a work that is in the public domain under applicable law, because our licenses only apply to works that are protected by copyright. So if a work is in the public domain, you can use it for whatever purpose you wish (though see below), without restriction or attribution. This is less restrictive than the various Creative Commons licenses, which require various levels of attribution, non-modification, etc. depending on the license chosen by the creator. 2. Trademark protections are separate from copyright protections Your quote from the government website implies that these logos might be trademarked, even if they're not under copyright; this is entirely possible. Roughly speaking, trademark protections keep other people from trading on your good name &amp; reputation; copyright protections keep other people from directly profiting from your creative endeavors. If another party creates a product that uses a trademark in a way that would create confusion among consumers, the trademark holder can sue for that. Depending on how you use the logos, you might run afoul of these protections. See this Q&amp;A for futher details under US law. (Australian law may differ a bit but I would expect that the general principles are the same.)
When the site says &quot;a license is highly recommended&quot; I can think of one possibility. A web site can be so designed that it uses a particular font if that font is already installed locally, but falls back to some other font if it is no0t, rather than embedding the font. Since the font in question is provided free for personal use, those who individually download it could use such a site. The designer of a font holds copyright on it, and may license it under whatever terms s/he chooses. If a person wants to design a web site with this as an embedded font, then it must be licensed from the rights-holder on whatever terms the rights-holder offers or will agree to. There does not seem any option but to pay the licensing fee if this font is to be used in a commercial site or product. Using it without permission would be copyright infringement. The rights-holder could sue for damages. Whether it is worth paying that fee is a matter of judgement for the site designer. But there does not seem to be any provision making a license optional for a commercial developer.
Not under US law Under the US copyright law, specifically 17 USC 203: a) Conditions for Termination.—In the case of any work other than a work made for hire, the exclusive or nonexclusive grant of a transfer or license of copyright or of any right under a copyright, executed by the author on or after January 1, 1978, otherwise than by will, is subject to termination under the following conditions: The conditions are somewhat complex, and I will not quote them here. The author or authors, or the heirs of the author or authors, or a majority of them, have the right to terminate copyright transfers an license grants. This termination must be effective on a date within a five-year period starting 35 years after the transfer or grant was made, or 35 years after publication. There must be a notice of intent to terminate, sent at least 2 and not more than 10 years before the effective date of termi\nation. Section 205 (a) (5) provides that: (5) Termination of the grant may be effected notwithstanding any agreement to the contrary, including an agreement to make a will or to make any future grant. Section 205 (b) provides that: (b) Effect of Termination.—Upon the effective date of termination, all rights under this title that were covered by the terminated grants revert to the author, authors, and other persons owning termination interests ... ... (4) A further grant, or agreement to make a further grant, of any right covered by a terminated grant is valid only if it is made after the effective date of the termination. As an exception, however, an agreement for such a further grant may be made between the persons provided by clause (3) of this subsection and the original grantee or such grantee’s successor in title, after the notice of termination has been served as provided by clause (4) of subsection (a). Summary Under US copyright law the author, co-authors, or the heirs of the author(s), or a majority of them may cancel a license during a specific five-year period No provision in the license or other agreement may waive this right, or bind the author not to exercise it. Open source and copyleft licenses generally do not mention this legal right of the author. Derivative (modified) works created under a canceled license may continue to be used, but the right to create new derivative works is withdrawn. It is not clear how an author goes about sending the required notice when a work was distributed widely to the general public under a permissive license. Open source licenses have been around long enough that early license grants could be subject to such terminations. But I have found not news reports or court cases about such terminations or attempted terminations and their effects. Probably most authors of open source software will not want to terminate the licenses they once granted. But some may, and US law gives them the right to do so. Users of software or other protected content under such licenses should be aware of these termination rights.