What is the general view on answers that reference material that infringes copyright?

Specifically, this question posted today contains an answer that references a PDF online version of the well known book: "Design Patterns: Elements of Reusable Object-Oriented Software". I strongly suspect this infringes the book's copyright and as an answer on Stack Overflow I think this is pretty bad form.


2 Answers 2


Edit: The following statement is my personal viewpoint only. There seems to be some legal uncertainty as to whether the suggested behaviour would be considered a good thing. I would suggest you read this related answer by Joel and the subsequent comments. Before taking any action based on this discussion. It may be better left alone.

StackOverflow is not for illegal file sharing. Flag it for moderator attention and note that the source is not legal.

Alternatively if you have appropriate edit privileges remove the link and replace with a note that the link was not legal. Perhaps replace with a link to the book on Amazon or the books website.

Remember SO is based in the US, and legality often differs between jurisdictions so don't be too harsh on the poster as they may not have been aware.

  • I see you got there before me :-)
    – Adamski
    Commented May 10, 2010 at 13:38
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    +1 for the international reminder. Commented May 10, 2010 at 13:40
  • @Adamski: Yeah, thought I would just clear it. I've noticed that the original link still remains in the edit history so I've still flagged it for mods. Don't know if they have the power to sort that or not, but I suppose they can raise it up to the SO team if not. Commented May 10, 2010 at 13:42
  • Wait, there are countries where copyright infringement is legal? Commented May 10, 2010 at 13:57
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    @Kop: There are countries with different copyright laws, although almost the whole world has laws based on the Berne convention. The US extended the Berne convention copyright times, so in general there's more under copyright in the US than other countries. Also, what constitutes infringement can vary. Commented May 10, 2010 at 14:04
  • @Kop: There are countries that don't respect others copyright laws, and the specifics differ from country to country. For example, some require a copyright notice, others require registration and the copyright term is often different. See wikipedia Commented May 10, 2010 at 14:06
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    Also remember that copyright length and the things that can be copyrighted varies dramatically from country to country.
    – perbert
    Commented May 10, 2010 at 16:49
  • They also vary dramatically from month to month.
    – forget it
    Commented May 10, 2010 at 22:32
  1. I don't think you can infringe on copyright by merely linking to a copy.
  2. IANAL, but even if you could infringe by linking my reading of the law is that if Stack Overflow wants to keep service provider protections provided by Section 230 of the CDMA, it must remain neutral — that is, it can never make the determination for itself of whether a particular use of a copyright-protected work is infringing or not. There are just too many places where the copyright holder wants their works distributed widely. Sometimes a copyright holder will even single out a few places to allow distribution for promotional reasons, as has already happened on StackOverflow at least once (the Telerik promotion for 10K users is a loose example of this). So it's entirely up to the copyright holder to notify the site of infringement. This means that flagging for moderator attention because of copyright issues is pointless. Now plagiarism (which also implies copyright violation) is another issue.
  • I kind of see your point, but in this case the book is quite clearly copyrighted and not distributed freely. The PDF linked is quite clearly illegal. Are you really saying the community can't moderate and make the decision that it doesn't want that kind of content linked to. It's the community making the decision, not SO the company. Commented May 10, 2010 at 13:50
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    @Simon: The fundamental issue here is that, once a site sets themselves up as a filter for X, they may be liable for violations of X. The DMCA in the US codifies this for some extent for copyright, by providing a "safe harbor" method for websites to operate. This question is best left for an actual lawyer. Commented May 10, 2010 at 14:08
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    @Simon - the pdf is probably illegal, but linking to a single illegal pdf is almost certainly legal (linking to a lot of illegal files with little other activity is still up in the air). In the long run, we probably don't want to encourage such links, because over time those links will tend to go bad. But the copyright view of the issue is that we have to leave it alone. Commented May 10, 2010 at 14:22
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    @David @Joel: I still don't get this. I'm not disputing the law, or your interpretation, but it just seems crazy. We are all agreed that nobody wants this kind of link on SO legal or otherwise (I presume), but seemingly the law says that if we remove them, SO becomes at risk of prosecution when a future link isn't removed fast enough. So the outcome is that SO (& the users) become unable to police the content on their own site. This just seems totally backwards to me. Perhaps this question needs an "official" standpoint from Jeff or the SO team so the community and mods know how to act. Commented May 10, 2010 at 16:19
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    I agree with @Simon. What happens if I start posting spam questions that have no content but only a long list of links to illegal material? You are legally prevented to delete them? So basically if I want to destroy SO I will just start posting 2-3 of such "questions" every minute and you won't be able to do anything about it? Commented May 10, 2010 at 16:23
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    @Kop: Of course not. They could (and would) be quickly deleted because, regardless of copyright issues, they are not fitting in with the purpose of the site. The tricky part that Joel is talking about is in regards to posts that do attempt to remain within the natural range of what the site is for ("answering programming questions").
    – beska
    Commented May 10, 2010 at 16:47
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    @Simon: IANAL, but I've seen some odd things crop up in law, and in this case it might be good to consult a lawyer. I don't think individual actions will hold the site to any liability, but an official policy might. The best reason I've got for making that comment is that I've got a bad feeling about this, and know just enough to make me nervous, so don't take this as advice (except for the part about consulting a lawyer). Commented May 10, 2010 at 20:13
  • @Simon - This is old now, but I do want to clarify one point in case you're still around. The legal issue here requires that we not take action on copyright grounds alone. That's why their's a distinction between copyright and plagiarism, and why we don't like link-only questions. You can edit for those reasons. Also, this only applies to agents of Stack Overflow - regular users can make any edit they want. Commented May 13, 2011 at 5:26
  • @Joel - Do you need me to update my response to clarify things? Commented May 14, 2011 at 9:34

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