This one leaves me with a bad taste in my mouth, but I defer to others as to whether it is appropriate or not. In this question, I wrote an answer to a question based on my experiences; it was upvoted and accepted, woo.

Now, today, in response to a different — but related — question, someone has pasted my answer nearly verbatim (awkward English intact, I may add) as an answer.

Is that really okay? Is it a behavior that should be encouraged? Discouraged?

  • 6
    FYI, I decided to look through that user's last dozen answers, and found another copy-paste. (To be fair, I also saw several answers that seemed to be original.) I'll flag that one and ask the mods to check that user's profile.
    – Pops
    Commented Feb 9, 2011 at 15:41
  • 2
    @Pop found one, too (assuming you mean this one): copied what's more, it's from a question that he himself asked first
    – Pekka
    Commented Feb 9, 2011 at 15:49
  • 2
    And another, copied from an external source
    – Pekka
    Commented Feb 9, 2011 at 15:51
  • 2
    And another, copied from here. Wtf. If you ask me, this is boot-worthy behaviour.
    – Pekka
    Commented Feb 9, 2011 at 15:54
  • 5
    And another, from here. This guy's whole OEuvre seems copy+pasted
    – Pekka
    Commented Feb 9, 2011 at 15:57
  • 19
    This is never tolerated. Please continue to flag it as you see it, as that's the only way we're going to detect it. We're taking these flags extremely seriously.
    – user50049
    Commented Feb 9, 2011 at 15:58
  • 2
    Another, copied from Vinko Vrsalovic (also flagged)
    – Pekka
    Commented Feb 9, 2011 at 16:05
  • 25
    OTOH, maybe we should get this guy to monitor the site for dupes. He seems pretty good at finding them! Commented Feb 9, 2011 at 16:46
  • 3
    @Adam I thought the same thing! His talent could be put to some use. :)
    – Pekka
    Commented Feb 9, 2011 at 17:23
  • 25
    WHY DIDN'T I THINK ABOUT THIS???? I'm copypasting Jon Skeet answers from now on.
    – user1228
    Commented Feb 9, 2011 at 18:11
  • 4
    IMHO, such duplicates should be downvoted, even if they're the perfect answer. The search could be automated, at least inside of SO it could be easily done.
    – maaartinus
    Commented Feb 9, 2011 at 18:18
  • 6
    @Joseph good point. @Shog9 went through most (all?) of them and converted them into properly attributed quotes, or links to the original source. That seems to be the most prudent thing to do in the future, although I would like to see the user's ass kicked in some way (at least by converting those contributions to CW)
    – Pekka
    Commented Feb 9, 2011 at 18:56
  • 3
    Ah, the user got a 24-hour ban. There is justice in the world, and whatnot. Also, nice janitor work, @Shog9.
    – Pops
    Commented Feb 9, 2011 at 20:53
  • 3
    @Pop the user came out of the suspension, apparently started editing out the "copied from xxx" additions, and got suspended again.
    – Pekka
    Commented Feb 11, 2011 at 9:34
  • 2
    @Pop yeah. This could have been written off as a massive misunderstanding of how to quote external resources, but that is proof that the guy knew exactly what he was doing, which seems weird (seeing as he must have some understanding of the issues presented in order to steal the right stuff). Maybe he is the prototype of an AI "answer-bot"?
    – Pekka
    Commented Feb 11, 2011 at 16:12

14 Answers 14


IMO, this is bad behavior on a couple of different fronts:

First an foremost, the rep system is based on the idea of representing a given user's standing in the community and ability to answer questions about which they have some technical understanding. The ability to copy and paste another user's answers does not a technical expert make.

Second, if the answer to one question truly is the answer to another question, then the original answer should be linked, not copied. This preserves authorship (or lack thereof, if the original answer is CW) and provides a single point of updating for the future.

What you have is, essentially, plagiarism.

  • It would also give some ability to consolidate questions in the future
    – jcolebrand
    Commented Feb 9, 2011 at 21:55
  • 4
    > Second, if the answer to one question truly is the answer to another question, then the original answer should be linked, not copied. In fact, it’s likely that the question is an exact duplicate for the other question, so it should be flagged, closed, and link to the older question.
    – Synetech
    Commented Jun 8, 2012 at 1:12

Adding to an answer by Adam

You can find this at the bottom of every page on SO:
user contributions licensed under cc-wiki with attribution required

It looks like, if somebody wants to post your work anywhere else, he must provide proper attribution, including referencing original author.

So, it's not only unethical and immoral, it also seems to be against the rules.


This is a little more "gray area"-ish than it initially seems. Technical understanding is key, but distribution is important, too. If nobody at question 2 can find the information posted to question 1, only the people who participated in question 1 are benefiting. Copy-pasting isn't inherently bad, as long as the answer is correct, on-topic and properly attributed in its new location.

Also, if I copy-pasted an answer, and the original answerer showed up with a similar answer, I'd delete mine out of courtesy. (For what it's worth, I've never actually copy-pasted an answer; I prefer the "post a relevant excerpt with a link" approach.)

Just to be clear: yes, I realize that in your specific case, attribution guidelines weren't followed. That's not cool.

Wow, this was not an isolated incident. Shog and Pekka found a couple of the bad eggs, but there were many more. Here's the list I came up with (EDIT 2: bullet points are things that happened after I posted this list):

  1. User comes though the proper path
    • Answer has been deleted
  2. How do I integrate a digital signature in PHP
    • Answer has been deleted, but another user posted an appropriate link to the page that was originally copied from
  3. Convert PHP HTML contents to DOC/PDF with remote images and stylesheets
  4. difference(s) between size_t and sizeof
  5. Help with .htaccess rewrite
  6. Ajax function calling
    • Author tried to edit the attribution out; answer has been locked
  7. Body overflow hidden problem in Internet Explorer 7
    • Answer deleted, then undeleted and replaced with a link to the original source
  8. MySQL saves tables names as lower case
    • Answer has been deleted
  9. GoDaddy PHP and shared Windows Server file uploading issues
    • Answer has been deleted
  10. How to upload preview image before upload through JavaScript
    • Answer has been deleted
  11. Go Daddy and magic_quotes_gpc
  12. Webpage won't parse PHP code
    • Answer has been deleted
  13. Validate phone number with JavaScript
  14. PHP comparison '==' problem
  15. https://stackoverflow.com/questions/4941667/how-to-show-all-the-item-in-the-database-that-i-choose/4941699#4941699

I edited all of these to contain attribution links except in cases where I saw that someone else already had. At least one of these comes from a website that explicitly states that copying its content is not allowed. I soft-deleted that, but it's still in the revision history.

  • 7
    Posting an excerpt/link is indeed the best approach. Better yet, a link in a comment on the question.
    – user102937
    Commented Feb 9, 2011 at 15:40

Another case. This user is also known for sock-puppeteering, which is why I decided to take a look. It's a bit shocking to see almost all contributions that consist of more than just a link to be plagiarism. Is this that rampant?

And more...

  • 3
    I cleaned up a couple of these by giving attribution when it was just a small part of the answer. The rest are just deleted. Thanks for pointing these out. ( Mental Note: Do not do anything to make @What suspicious. ) Commented Mar 22, 2011 at 17:10
  • 1
    @Bill you're welcome and thanks! Plagiarism policework is actually kind of fun. :)
    – Pekka
    Commented Mar 22, 2011 at 17:53

When I refer to another post elsewhere, I quote the post and link to the original reference, like so:

Jack had an experience that might help you, which he posted in response to a similar question about widget X. Here's an excerpt:

When I was just a wee little lad, my Daddy brought to me a toy he made down at the lab; it filled me full of glee! A wonder to behold it was, with many buttons bright from the moment that I turned it on, it filled us all with fright!

It went ZAP! when it fired; it cursed when it missed and whirred as it took aim. It didn't know if we were friend or foe it attacked us just the same

It allows one to refer to the original answer, provides attribution, and helps people understand that this is not original material.

I suggest when this happens you edit the post if possible to comply with the above format. If you can't edit, or you choose not to, add a comment with a link to the original and flag it for moderator attention requesting that attribution be added to the post.


Another one! Discovered by mootinator.

The user seems generally helpful and knowledgeable though - I went through about 25 of his answers, and found only 3 instances of plagiarism. It's still not ok, and I'm sure if somebody were willing to sift through the entire list they would find more.


There are two sides to this:

As a questions asker:

I don’t care if a good answer is copy-pasted from elsewhere if it solves my problem.

As someone that reading a question to solve a problem


As the persons that wrote the answer that was copied.

I do care about lost rep etc.

There is also the issue that the same answer may need to be edited in lots of places if it needs updating.

So we need to define “bad behaviour” relative to different sets of interests.

  • 4
    As long as the post is properly attributed, it doesn't matter to me. But copy/pasting an answer without crediting the original author is a bit smarmy at best.
    – user102937
    Commented Feb 9, 2011 at 15:39
  • 2
    That last issue is, to me, the most concerning. Even with attribution, a full-on copy won't easily be kept up-to-date.
    – Shog9
    Commented Feb 9, 2011 at 15:45

Another case. Not as massive as some others, but this gal or guy is just getting started!

I think that's it.


There is a new case. I'm posting this here because it seems like the best place at the moment. I don't think this user is as malicious as the original case though, he does provide original content (and many properly attributed quotes and links). Still, this is unacceptable and needs a warning.

Edit: The user is adding links where they were missing and removing unattributed content, so I think it is safe to assume good faith.

Edit 2: A second check two months later shows this user isn't doing unattributed copies any more. Nice!

  • Just saw that your 4th Answer link points to the same target as "this article". Commented Apr 16, 2011 at 7:53
  • @Hendrik thanks. The answer in question seems to have been deleted since, so I can't fix it!
    – Pekka
    Commented Apr 16, 2011 at 8:04

Another case. Rather sad, the C&P jobs are so dumb....

Edit: Mission accomplished. Yay, Bill the Lizard and Kev!


... and another case, stumbled upon while researching the previous one.

User profile

I didn't check every contribution in depth, but this should cover all or most plagiarism from this user.


I think it is plagiarism. If the answer is at another place (within stackoverflow) then there is high chance that the two questions are similar. So, the user can simply add a comment mentioning the related article. This will also help linking these two articles.


One should just keep it like in academia and provide the source. There are many cases in which one can't find the question to an answer in one place and then you find it somewhere else. So why shouldn't you let the others participate in that knowledge that you found somewhere else? As long as you keep the author and inventor in honour and provide his name, username and a link to the source, this is an absolutely appropriate behaviour that adds value to everyone: The people who are still seeking for a solution get a solution from another source. The author who provided the solution gets the credits that he deserves. And the community profits from better informed individuals and the spirit of sharing. So there is absolutely nothing wrong about "citing" other sources - indeed it would be value destructing not to do it.


Well I must appreciate if answer is helpful. Suppose I don't know the answer of a question comes my way But I know the source, then what should I do? My common sense suggest me: Just tell the source. It is not bad for me. Not at all :)

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