Is it copyright infringement if I make a work of art that has already been made before? Take modern art, for example. People draw a circle and call it art, and apparently it automatically has a copyright after it's made. Then I come along and draw another circle and call that art, and it looks very similar. Would that be against the law because someone has already made it before, or can I use it if I have proof that I didn't copy their art? And keep in mind I don't know much about this because the only law experience I have is from Wikipedia.
This sounds like a case where there can be differences as to if something is a design that can be copyrighted or if it is a matter of a trademark held by the artist who drew the circle. If someone began a copyright infringement action against you, claiming copyright of the shape of a circle, your defense could be the Threshold of originality (Wikipedia). The threshold of originality is a concept in copyright law (Wikipedia) that is used to assess whether a particular work can be copyrighted. It is used to distinguish works that are sufficiently original to warrant copyright protection from those that are not. In this context, "originality" refers to "coming from someone as the originator/author" (insofar as it somehow reflects the author's personality), rather than "never having occurred or existed before" (which would amount to the protection of something new, as in patent protection). Obviously, circles, squares, triangles, pyramids, etc., even straight lines, have all existed for a long time. Simple shapes can, of course, be included as part of a more complex design, and that design as a whole is copyrighted as soon as you complete the design. You don't need to claim copyright; you already have it. If you did a design that was fairly simple and were accused of copyright infringement, it might come down to a court case to determine the threshold of the threshold of originality. Now, if you did a painting of a circle that looked like another painting of a circle, then you could be accused of trademark infringement, because the artist you allegedly copied could say that they have such a distinctive style that is is their trademark. A trademark, trade mark, or trade-mark is a recognizable sign, design, or expression which identifies products or services of a particular source from those of others...Trademarks (Wikipedia) Trademarks are also designs, of course, but are protected in a different method different than copyrights. So many decisions about copyright infringement come down to the judgement and opinions of a jury, because of the fungibility of what exactly constitutes originality and what constitutes a copy, part of a copy or a derivative. Trademark infringement hinges on how recognizable that design as a mark is and if there can be confusions between the two. For a much more in depth outline of copyright, see I have a question about copyright. What should I read before I ask it? - Law Meta Stack Exchange.
Well, actually, fair use is maximally relevant. Copyright means, put simply, DO NOT COPY. Citing or not is irrelevant (plagiarism is a whole other non-legal kettle of fish). Technically, what you describe is violation of copyright. However, under section 107 of Title 17 (the copyright law), you could attempt to defend yourself against an infringement suit on the basis that your action was "fair use". See this LSE q&amp;a for the essentials of fair use.
It is illegal to make copies of copyrighted materials without license. In the case of software, obviously it will be illegal to make copies by copying and installing the software without a license, but we are not talking about that. If I have a legitimate license of say Photoshop, and I start the application, parts or all of the code will be loaded into the RAM of my computer, which is a copy. According to copyright law, it is legal for me to make that copy. You are allowed to copy legitimately owned software into RAM to execute it. If your copy of Photoshop is illegal, and you start the application, the copy that is made into RAM is again copyright infringement. Having read the software license for the software that you get when you buy a Mac, it seems that if you steal my computer and just start the operating system, you are committing copyright infringement, and it seems that if you buy such a stolen computer and just start the operating system, you are committing copyright infringement as well, because the license that I received when I purchased the computer covers anyone using it with my permission, and covers anyone who legally buys the computer from me, but doesn't cover a thief. Now does this affect the work that you did? No, you have the full copyright on your work. Copyright law doesn't require that your tools are all used legitimately.
Whoever "derived" the illegal derivative work most likely has copyright in his derivations, unless they are not worth copyright protections. Say I take the Harry Potter books and add a few chapters and try to sell it - that's copyright infringement of course, but I have the copyright on these additional chapters. However, I don't have the right to allow you to copy the derived work. And even if you have the right to copy the original work, you don't have the right to copy the derived work because it is a different work. I could extract my changes, and allow you to take them and do with them what you like. You could then create an illegally derived work yourself. I couldn't sue you, but the original copyright holder could. To the comments: One, a work and a derivative of the work are not the same, so even if you have the right to make a copy of a work, that doesn’t give you any right whatsoever to copy a derivative work - they are not the same work. Two, the copyright holder has the exclusive right to control copying and the creation of derivative works. If the copyright holder doesn’t want derivatives to exist, then creating them, copying them etc. is always copyright infringement.
If soemoen sues you for infringement of a design copyright, it would be a valid defense that the plaintiff had in fact taken the design elements from your prior work, or indeed from the work of a third party, and so had no valid copyright. Proving this may be easy or hard, depending on the specifics of the situation. Registration will prove that your work existed and you claimed it as original on a specific date. It would not be a perfect defense: if the other party claimed that you had copied prior to that date an infringement action could proceed. The effect of registration is somewhat different in US law and the law of various EU countries. In the US, for one thing, one must register before bringing an infringement suit, and the date of registration may affect the availability of statutory damages, and of an award of the costs and fees for bringing suit. Note that the protection offered by a design copyright is limited: copyright will never protect an ide3a or concept, and so only the specific expression of a design can be protected by copyright. What this means will vary in particular cases. Specific artwork or logos will each carry its own copyright, and if they are original creations of yours, you can register them. (These would not be design copyrights, but ordinary copyrights.) You can also obtain a single registration for the website as a whole. It is very unusual for one who copies a work, or elements of that work, to then sue the original creator for infringement. Given the existence of archive services, it is often fairly easy to prove how a site looked on a particular date. Ensuring that your site has been archived as soon as possible would make it easier to show that it was not copied from a later work. Some services will archive a particular site on request.
You misunderstand the nature of copyright. Holding copyright allows you to decide how the work can be copied: there is no obligation on you to publish it if you don't want to. After your copyright expires you don't have to publish it either: the only thing that has changed is you can no longer prevent anyone making a copy. The lost works of Aristotle are in the public domain - if you can find them you can make as many copes as you like.
There are now 2 works. An original, abandoned work, and a new, derivative work. The original creator owns the copyright over the original, and the new person owns copyright over the derivative he created. In your scenario, it will be the new creator, who will have the right to sue, if the gpl of the new work has been infringed
You can do whatever you like with posts made after you change the rules - you have to leave the previous stuff alone. The contributors' have accepted the terms of the licence: They own the copyright or have permission from the copyright holder to post it (the promise) They agree that it can be edited altered or removed CC-BY-SA allows people to copy the stuff off the website and republish it - this is way outside what the contributors agreed to. These people have given permission for their work to be altered but not copied.