As prompted by NullUserException อ_อ, I'd like to try get a definitive moderator view on what is the appropriate action when a user spots an obvious copyright violation on Stack Overflow.

To be clear, I have a reasonable understanding of fair use and am myself not averse to posting small extracts of code to which I do hold rights. What I am talking about is when large extracts of code are posted in clear and obvious violation of rights holders.

This issue has been prompted by a couple of recent questions.

Why was this question deleted over code allegedly copyrighted by Embarcadero?

This question was flagged (not by me) as containing copyright code and then deleted by a moderator who stated:

I was the one that deleted the question, and answer, and the reason was that all the code is lifted from source code copyrighted by Embarcadero.

[Aside: I am as sure as I can be that none of the deleted code is copyrighted by Embarcadero.]

However, another moderator, not involved with the voting and deletion on the disputed question has stated:

In order for a moderator to remove infringing content from Stack Overflow, the moderator must be able to verify that copy-pasting took place. In the absence of that verification, a better course of action is for the copyright holder to provide SE corporate with a DMCA take-down notice.

Moderators make every effort to remove copy-pasted material when they can, but they cannot get involved in copyright disputes, for a number of reasons:

  • Mods cannot always verify that copyright infringement is taking place.
  • Mods don't have the power or the authority to fully act on copyright issues.
  • Mods do not know the intent of the copyright holder.


Before flagging such questions, consider raise the issue with the OP first by posting a comment on his question. It's possible they will voluntarily comply.


But the only persons/entities that can raise a copyright claim are the copyright owners themselves, and the only way they can legally do that is by issuing a DMCA takedown notice to SE corporate.

Creating replacement TApplication for experimentation?

I flagged this question:

The code posted here is copyrighted by Embarcadero and comprises key chunks of the TApplication class from Forms.pas

This flag was declined: a moderator reviewed your flag, but found no evidence to support it.

I don't think there can be any debate that the code in this question is copied from the Delphi VCL source. The user asking the question states this! [Aside: Perhaps the reason for declining the flag should have been more informative.]

Another question, which I cannot locate

Recently I raised in comments what I believed to be an unattributed lift of a P/invoke declaration from pinvoke.net (the two declarations were identical character for character) in a Stack Overflow answer.

This is pretty benign and I just suggested to the answerer that the original source should be credited. This rapidly descended into a comment war which I should have exited much sooner than I did. A moderator told me off for this (justifiably) and I asked how I should have handled it. I was told that I should not have used comments since this would inevitably be provocative and instead should have flagged.


It seems to me that there is a deal of confusion around this issue and its treatment by moderators. I would like to ask how a member of the Stack Overflow community should handle obvious copyright infringements. I am hoping that this question can result in definitive guidance.

One final point, and this is a bit of a gripe. I find the inconsistency of moderation disconcerting. The two questions I linked to had exceedingly different responses. The first had no copyright issue yet the question was deleted and a very forceful message left by a moderator. The second had as clear a violation as ever there could be, and yet the flag was declined. This does not encourage community members to contribute to the running of the site.


2 Answers 2


Short answer: If you see material that shouldn't be on the site, flag it with a clear explanation of why you think it shouldn't be there. However, don't make a copyright claim in your flag; moderators are not equipped to deal with these.

Copy-Pasted Material
Moderators (and community users) can delete content that has been verifiably copy/pasted from other sources, or references material that clearly doesn't belong (e.g. links to PDFs of books from reputable publishers).

Moderators may delete copied material (even if the copying is not verifiable), if they believe that the flagger is acting in good faith and has personal knowledge of the copying taking place.

Note that this form of deletion does not remove the offending content from edit histories, and users with 10K reputation or more can still see content deleted in this manner.

Copyright Violations
The Digital Millennium Copyright Act has a "safe harbor" provision that protects ISPs if someone posts copyrighted material, provided the ISP responds to properly-formatted takedown notices from copyright holders by removing the offending material.

Properly formatted take-down notices contain all of the following:

  1. Contact information.
  2. The name of the material that was copied.
  3. The address (URL) of the copied material.
  4. A statement that the person filing the take-down notice has a good faith belief that use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.
  5. A statement that the information in the notification is accurate.
  6. A statement that, under penalty of perjury, the person filing the take-down notice is authorized to act for the copyright holder.
  7. The signature of the person filing the take-down notice.

Moderators do not have the authority or ability to respond to such requests, nor does a moderator flag meet the requirements of a properly-formatted takedown notice. DMCA take-down notices should be directed at SE Corporate.

Material removed under this provision cannot be viewed by any user of Stack Exchange. It is a complete deletion from the database and edit histories.

What to do if you see a problem
In practice, SE Corporate and the community reserve the right to remove material at any time and for any reason (See https://stackexchange.com/legal, section 3). So if you see something hinky happening, flag it.

Use the word "copyright" in your flag if you wish, or don't use it; just understand that mods don't have the ability or authority to respond to claims of copyright infringement; they can only respond to "bad things happening." In turn, you don't have the authority to act on behalf of the copyright holder, but you do have the right and obligation to let us know that there are "bad things happening."

Should I discuss this with the infringer?
My personal preference is that you do not use comments for this; if the person posting the infringing material thought they were infringing, they wouldn't have copy-pasted the material in the first place, making this a contentious issue for them. But not everyone agrees with me on this point.

  • You say: "Moderators (...) can delete content that has been verifiably copy/pasted from other sources". Why not "can (and probably should)"? Based on my experience, copy-pasted material are very easy and straightforward to get "deleted" by an admin (history included) on Wikipedia, as opposed to SO, due to this kind of flabby policy IMHO. I think it can protect SO as much as it protects Wikimedia from laws like this one you guys fear. It would also, in a way, prevent law-makers from thinking of it at the beginning.
    – Totor
    Commented May 1, 2013 at 14:08
  • @Totor: Welcome to the American legal system.
    – user102937
    Commented May 1, 2013 at 14:46
  • ?? I was criticizing the lack of a strong enough deletion policy on SO, and how it is reflected on your answer ("can delete" instead of "should delete"), not the law! Mentionning it was merely done to make my point...
    – Totor
    Commented May 1, 2013 at 23:38
  • @Totor: This would be very simple if it didn't involve legal issues.
    – user102937
    Commented May 1, 2013 at 23:39
  • It doesn't! I'm quoting you: "SE Corporate and the community reserve the right to remove material at any time and for any reason". It has never been a problem on Wikipedia, as long as it does not turn into censorship, but we are talking about copy-paste here!
    – Totor
    Commented May 1, 2013 at 23:42
  • Well, I spent a lot of time writing a long answer for nothing then.
    – user102937
    Commented May 1, 2013 at 23:44
  • Edit, dude: "can" => "should".
    – Totor
    Commented May 1, 2013 at 23:44
  • 1
    Moderators are not responsible for policing SE sites for copyright violations.
    – user102937
    Commented May 1, 2013 at 23:46
  • "should delete" does not involve any "responsibility" for anyone. It is different from "must"... Come on! one does not need to be a lawyer to recognize a copy-paste! I think you/we should support and encourage deleting content from "verifiably copy/pasted" sources, as you say. How could we ever complain after that, that our GPL or cc-wiki licenses are getting trampled by big companies? Look at us.
    – Totor
    Commented May 2, 2013 at 0:00
  • so if someone in their book has written OOP should be written this way: XYZ, 1. can I copy and paste that with attribution (like only 5-6 lines)? or 2. can I rewrite what the author has said + attribution or 3. just write on my own and say nothing? (I'm not asking a legal question, only asking about SO rules)
    – Honey
    Commented Mar 14, 2017 at 15:16
  • 2
    @Honey: Read up on "Fair Use." In general, you can quote short passages with attribution, and you should be OK. Ideas are not generally copyrightable, so if you say something in your own words, you should be OK. It's polite to attribute where you got the ideas from.
    – user102937
    Commented Mar 14, 2017 at 16:04

There's some official guidance about this in the April 2012 moderator newsletter. Most relevant snippet:

... you are not employees of Stack Exchange. In essence, you are free to moderate the site for content how you see fit. If you are ever notified about copyrighted material, and feel like taking it down, that’s cool... but you are not required to do so. You are not DMCA agents ...

(bold text is original)

  • This answer provides some guidance on expected etiquette for attributed citations — which one presumes are covered under fair use and therefore not actual copyright violations. Although it was posted to the ELU Meta, I believe it to be a general network-wide policy, given that it was crafted in consultation with SE staff and their official materials.
    – tchrist
    Commented Mar 16, 2015 at 14:08

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