Open source licence reproduction If an open source software licence requires to "preserve this notice", which usually appears within the source code file, and I'm not distributing any parts of the source code (but only binary files), does that mean that I don't have to do anything with that original licence? Or would I have to create a new file with that licence notice, or include it into some documentation or even let the application reproduce the licence notice on the screen? Does it matter whether the original licence was embedded in the source files or distributed as a separate file? I'm thinking about shorter licences like BSD or MIT, or even those called "public domain". AFAIK the GPL or LGPL require distributing the separate licence text file as it's quite lenghty. I don't know about other licences like Apache or CC.
Both BSD and MIT require you to share "the notice" even when only distributing the software in binary form. For BSD: "Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.". For MIT: "The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.". What you need to do is to include these licenses in a "LEGAL"/"LICENSES" folder of the download package.
You need to check what license the library comes with. The fact that you want to create a public domain program doesn't give you any rights to any library. So read the BSD license and see what it tells you whether and how you can use the library. For example, if you used a GPL-licensed library, you could not put your program in the public domain legally.
Alice has been developing her own enhancements, and they're pretty similar to Bob's. Neither Alice nor Bob has copied the other's enhancements, so neither has violated the other's copyright in the enhancements. Whether that could be proved in court is another matter, of course, but since the original work is licensed under creative commons the question unlikely to arise in court. Would Alice be prevented from coming up with enhancements to her own game if other people could prove they thought of and released the idea first? No. Copyright does not protect ideas. It only protects a particular expression of those ideas from being copied. Theoretically, if two authors come up with identical 500-word descriptions of something and can establish that each did so independently, neither has a claim against the other. The practical problem there, of course, is that it would be impossible to prove such a thing. Could Alice outright claim Bob's "Adapted Material" because he developed it on her original work? Assuming that in publishing his adaptations Bob followed the terms of the creative commons license with respect to the original work, Alice's only claim would be that he copied her adaptations without following the terms of the license. If Bob can show that he did not do so, her claim would fail. In a comment, you wrote: Suppose Alice went ahead and intentionally, somehow provably ripped off Bob's "Adapted Material" because she liked the content so much, does Bob reserve any rights on his adaptation, or is Alice able to commercialize the work that Bob did in extending her original work? If we assume that Bob complied with the license of the original material, we know that he licensed his adaptations under "the identical terms," so Alice would be able to use Bob's adaptations under those terms for non-commercial purposes. Since the assumption here is that Alice provably copied something of Bob's, I think it is fairly clear that she would be liable for damages if she exploited that material commercially without paying royalties.
Affirmative authority that this particular use (incorporation of the format of another program's textual data files into your own program) is protected is somewhat elusive in the US system; however there's a lot of observable evidence that reverse engineering data file formats without a license is widespread. My sense is that this would be analyzed under the same rubric as other kinds of reverse engineering and/or fair use. I'm sure there are others here who are better able to clearly and concisely explain that law than I am. However there may be limits — it seems Microsoft was able to prevent VirtualDub's use of the ASF format by patenting it. That said, it's hard to see how an unencrypted, unencoded ASCII data file file could be patentable (i.e. where the ASCII strings are the data, generated in response to user input, and the format is just their order and separators, etc). For the European arena, there is recent authority in SAS Institute Inc v World Programming Limited that the format of a program's data files are not protected by copyright when reverse engineered without the source code. The following is from the digest and application of the CJEUs decision by the English court that referred it, in its subsequent judgment: The judgment of the CJEU On 29 November 2011 Advocate General Bot delivered his Opinion on the questions referred... Questions 1-5 The Court dealt with these questions together. It interpreted this court as asking "in essence, whether Article 1(2) of [the Software Directive] must be interpreted as meaning that the functionality of a computer program and the programming language and the format of data files used in a computer program in order to exploit certain of its functions constitute a form of expression of that program and may, as such, be protected by copyright in computer programs for the purposes of that directive": see [29]. Having referred to recital (14), Article 1(1) and 1(2) of the Software Directive, Article 2 of the WIPO Copyright Treaty and Articles 9(2) and 10(1) of TRIPS, the Court went on: ... 39. [...] it must be stated that, with regard to the elements of a computer program which are the subject of Questions 1–5, neither the functionality of a computer program nor the programming language and the format of data files used in a computer program in order to exploit certain of its functions constitute a form of expression of that program for the purposes of Article 1(2) of Directive 91/250. 40. As the Advocate General states in point 57 of his Opinion, to accept that the functionality of a computer program can be protected by copyright would amount to making it possible to monopolise ideas, to the detriment of technological progress and industrial development. 41. Moreover, point 3.7 of the explanatory memorandum to the Proposal for Directive 91/250 [COM(88) 816] states that the main advantage of protecting computer programs by copyright is that such protection covers only the individual expression of the work and thus leaves other authors the desired latitude to create similar or even identical programs provided that they refrain from copying. 42. With respect to the programming language and the format of data files used in a computer program to interpret and execute application programs written by users and to read and write data in a specific format of data files, these are elements of that program by means of which users exploit certain functions of that program. 43. In that context, it should be made clear that, if a third party were to procure the part of the source code or the object code relating to the programming language or to the format of data files used in a computer program, and if that party were to create, with the aid of that code, similar elements in its own computer program, that conduct would be liable to constitute partial reproduction within the meaning of Article 4(a) of Directive 91/250. 44. As is, however, apparent from the order for reference, WPL did not have access to the source code of SAS Institute's program and did not carry out any decompilation of the object code of that program. By means of observing, studying and testing the behaviour of SAS Institute's program, WPL reproduced the functionality of that program by using the same programming language and the same format of data files. 45. The Court also points out that the finding made in paragraph 39 of the present judgment cannot affect the possibility that the SAS language and the format of SAS Institute's data files might be protected, as works, by copyright under Directive 2001/29 if they are their author's own intellectual creation (see Bezpecnostní softwarová asociace, paragraphs 44 to 46). 46. Consequently, the answer to Questions 1–5 is that Article 1(2) of Directive 91/250 must be interpreted as meaning that neither the functionality of a computer program nor the programming language and the format of data files used in a computer program in order to exploit certain of its functions constitute a form of expression of that program and, as such, are not protected by copyright in computer programs for the purposes of that directive." Regarding the idea that the user has rights to access their output of a program held in a proprietary data file format there is some additional discussion in the that might be helpful in paragraphs 48 - 62 (of the CJEU opinion), discussing the right of a licensee to 'study and observe' the 'underlying' 'ideas and principles' of a program to accomplish 'acts of loading and running necessary for the use of the computer program.'
Udemy claims that all the videos and course content are copyrighted, but does that also hold for the material of the course? Yes, all the material is copyrighted. Ideas are not, material and content is. it would be really useful to me if I could take a large part of that code ... I want to know if I am allowed, by the law, to use this code for commercial purposes, or is it protected as the intellectual property? Yes, it is protected, specifically it has copyright applied and you may only use it if the license it is distributed under allows you to - in some cases this may be a permissive license, or the code may be obtainable legitimately from another source under a permissive license, in which case its usable. But in many cases, it may not be distributed under a permissive license or indeed any license, and in such cases you will not be permitted to use it. The license under which the code is released depends on the individual course, and in many cases the source code repository or download site for the code for the course. Check their for a license.
What you're talking about is called black-box reverse engineering. It can be done, and as long as you are meticulous in your record keeping the fact that it has been done should be an appropriate defence against copyright infringement. But that doesn't help against patent claims - while in copyright cases the fact that code has or has not been directly copied is critical, in patent cases it its irrelevant: if you use a patented method, it's a violation. You therefore will need to be careful about any patents that may have been issued to the original author, as well as avoiding copying.
A GPS trace of a car's path, on its own, is unlikely to be covered by copyright in the first place. It is primarily made up of facts (the locations of roads and lanes), and there is no creativity involved in its creation. A database of facts may be protected by copyright as a compilation if there is some amount of creativity in how it is assembled, but this does not extend any protection to the individual contents of the database (cf. Feist v. Rural).
The code and the “look” of the user interface is protected by copyright - you can’t duplicate either. You can create your own app with the same functionality.