How can we answer questions about tabletop game rules without infringing copyright? https://rpg.stackexchange.com/ is a stack dealing with table top RPG games, the most prominent being Dungeons and Dragons (D&amp;D). Answering questions almost always relies on information from rule books sold by the makers of D&amp;D. Due to stack culture reasons, answers directly referencing the rules are valued far more than experienced perspectives. To avoid link rot, it is essentially a requirement to copy-paste the relevant portions of the rules into the answer. These portions could be a few sentences, or even a few paragraphs, often they are the entire rules for a spell or character ability. Even answers that do not directly quote the rule books often use information from those rulebooks to write an answer. Ultimately SE is using this content to turn a profit, so we can't naively think we are merely sharing information with friends and are immune to copyright law. Are we actually allowed to share this pay-walled information? To what extent is this kind of content infringing copyright? What should we be looking out for to prevent issues?
This kind of quotation, for commentary, criticism, or reference, is generally allowed without obtaining permission. In the US, this falls under fair use (see 17 USC 107. In the UK and most commonwealth countries, it falls under fair dealing. In other countries there are various exceptions to copyright that will probably cover this. Even answers that do not directly quote the rule books often use information from those rulebooks to write an answer. Facts and ideas are never protected by copyright, so this is not going to be an issue. See 17 USC 102(b), which provides: (b) In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work. As a comment by user Trish reminds, game rules are facts and are not protected, although their exact wording may be.
The basic principle about copyright protection is that the expression of an idea is protected, but the idea itself is not. So wholesale copying without permission is infringing. But the abstract algorithm is not protected by copyright (and let us assume that it also isn't patented). By way of analog, an insertion sort is a pretty easy concept to grasp, and once you understand it, you can re-create it, independent of how the original example (where from you learned about the sort) is expressed. So the question is whether it is necessary for you to copy that code (copyright protects against copying), or can you independently re-express the algorithmic idea (ideas are not protected)?
As for plagiarism, that is not a legal concept, so he can define plagiarism however he wants. It certainly isn't, under any definition I have ever seen on Earth and I have seen many (it has to do with "claiming someone else's work as your own"). As for copyright, a set of questions is (potentially) protected by copyright. If they are copied from somebody else's book of questions, then the book author (or publisher) holds copyright. Let's say that QM invented the questions, such as "What is the Turkish word for Janissary?", "What is the most prominent feature of Jannissary garb?" and so on. Then that set of questions, when put down in fixed form, are protected by copyright, and cannot be copied without permission.
It should not surprise you that copyright protects the right to (among other things) make copies. There are limited exceptions that are considered &quot;fair use&quot;, like if you reproduce a limited amount of text for educational, reporting, or review purposes. Giving your friend a copy of a large portion of the text just because they want it would almost certainly violate copyright. Whether the book is available or out-of-print has absolutely no bearing whatsoever on who holds the copyright or whether your actions violate it. This is very different from giving your friend the book itself. The book itself is covered under the &quot;first sale doctrine&quot;, meaning that by buying a copy of the book, you buy the right to sell, transfer, or dispose of that particular copy, but it doesn't give you the right to make more copies. I will note that in practice, it is vanishingly unlikely that the copyright holder would ever learn of your isolated instance of limited infringement in the first place (especially since it's out of print), much less bring legal action against you for making a single copy that did not affect their bottom line.
You are creating a derivative work. You are only allowed to do this if the library comes with a license that allows this. If you want to give your derivative work to anyone else, copying it is copyright infringement unless the license allows it. Copying the derivative work and attaching a different license is most likely to be copyright infringement. And if people receive a copy with an open source license that is not justified and rely on it, that’s creating one unholy legal mess for everyone involved and can be massively more expensive than plain copyright infringement. No license means you don’t have permission to do anything with it, not creating derivative work, not distributing it, and certainly not publish it with an open source license.
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Copyrights don't apply to the names used. You mean trademarks. You copyright your game and you trademark the name. http://www.reddit.com/r/gamedev/comments/11v69k/using_a_guns_name_in_your_video_game/ Basically, it wouldn't be wise to use trademarked names in your game. Even though it's unlikely you would be sued and even if you were, you could possibly fight it under Fair Use, but do you want to take the chance? If some gun company decided they didn't like how you used their name, even if they have little to no grounds for a case, they can STILL sue. Anybody can sue for pretty much any reason where there is doubt. If they have enough money to throw around, they can drag you through the mud, ruin your business and then just lift their lawsuit. They don't need to win in court, just destroy you. Keep in mind that even if you don't use the name, if the gun in your game is an accurate replica of the real thing, it could still be a trademark issue. EDIT: Something you could consider though is asking permission. You never know. They may simply not care. You might even try propositioning them to pay YOU to have their gun showcased in your game. It's not entirely uncommon for companies to be willing to pay for a bit of endorsement advertising.
Under the Berne Convention, a copyright notice is not required at all, although using one is good practice. Using one usually eliminates the claimed status of "innocent infringement", which, if found true by a court, greatly reduces damage awards. It is usual to place such notices at or near the start of a work. That is where people tend to look for them, and I don't see any good reason not to follow this practice. The book tradition is the the copyright page comes before any part of the actual work, including the table of contents, sometimes with a continuation at the end of the work, if there is more than one page of notices. But that is not now a legal requirement, if it ever was. In short, there are no rigid rules on this, but putting a copyright notice at or quite near the start is good practice, and I would suggest sticking to it.