I've just posted an answer that includes a link to an XKCD cartoon that is closely related to the topic. Is it appropriate to include such humor in an answer?

  • 3
    The only crime is to A) not include the actual xkcd image and B) to not include the hover text. Oh, and C) to not include an actual answer along with it.
    – RubberDuck
    Commented Aug 21, 2015 at 20:53
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    And d) not attribute it?
    – kdopen
    Commented Aug 21, 2015 at 22:26
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    I've locked the post in question for the meantime (it will expire after one day), so that we can get this sorted out.
    – Zizouz212
    Commented Aug 22, 2015 at 16:21

3 Answers 3


Absolutely it is.

As long as an answer still answers the question, linking to external resources, be they serious or comedic, is fine and actively encouraged.

This only becomes a problem when the humor is out of place or is the only thing in an answer, which is not the case here.

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    It's also a problem when the image is CC BY-NC licensed and the person included the image is not the copyright holder... (see my answer) Commented Aug 22, 2015 at 15:06

As long as the cartoon isn't the only component of the answer, it's fine. Pictures are encouraged to make up a supportive section of an answer. Having taken a look at your answer, it looks perfectly fine, you could always embed the picture :)

However, if an answer is only a picture, or only a link, or only a quote...

None Shall Pass!

  • 1
    The irony of this.
    – ArtOfCode
    Commented Aug 21, 2015 at 17:44
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    @ArtOfCode Yep :D
    – Zizouz212
    Commented Aug 21, 2015 at 17:44

I hate to be a party pooper... but the answer as it was when I wrote this (see edit note) is infringed on XKCD's copyright.

You are required to:

  1. provide the name of the creator and attribution parties
  2. a copyright notice
  3. a license notice (name and link to the CC BY-NC 2.5 license)
  4. a disclaimer notice
  5. a link to the material
  6. the title of the material (I guess that would be "PGP")

Finally... all "user contributions" on stack exchange are licensed under the CC BY-SA license which is incompatible with the CC BY-NC license.

I'm not a lawyer but I think because of this last point it might be illegal (criminal in some countries with severe statutory damages) to include an XKCD comic in your answer even if you comply with the 6 things I listed above.

Thene answer including the comic can (and probably will) be used for commercial purposes. The XKCD's license prohibits releasing the comic under a license that allows commercial use.

This answer has some relevant details: https://opensource.stackexchange.com/a/1252/436

In summary, on topic humour is appropriate but not when it's licensed under terms that prohibit posting it here. You can probably only post a link to the comic page, rather than the image.

edit note

The answer in question originally contained a link to the comic, then somebody else edited it to include the image, and it has now been reverted back to having just the link.

  • 2
    You are allowed to link to the image. I'm not sure I see much wrong in that.
    – Zizouz212
    Commented Aug 22, 2015 at 15:13
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    @Zizouz212 you can link to the image, but you can't distribute copies of the image, which is being done here. Commented Aug 22, 2015 at 15:21
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    I followed the instructions on the XKCD site. Someone edited the link. I deliberately did not copy the image to SE for the reasons you mentioned. Commented Aug 22, 2015 at 15:33
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    I've rolled back the edit, to make it a link not an embedded copy. Commented Aug 22, 2015 at 15:35
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    @GlennRanders-Pehrson ah thanks, I've updated my answer to contain a summary of the confusion... I even looked at the edit history but because it highlights text in red/green (doesn't work on images) I failed to notice that somebody else embedded the image in your answer. Commented Aug 22, 2015 at 15:41
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    @GlennRanders-Pehrson I followed xkcd's license to the letter when I embedded that comic."That is, you don't need my permission to post these pictures on your website (and hotlinking with <img> is fine); just include a link back to this page"
    – RubberDuck
    Commented Aug 26, 2015 at 20:58
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    The trouble is that by embedding, it becomes CC-BY-SA (losing the -NC restriction), as stated in this answer. BTW, whether it's right or wrong, there's a large number of embedded XKCD comics, more than I care to count, on stackoverflow. Commented Aug 26, 2015 at 22:46
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    @AbhiBeckert Hmmm, Super User uses it for not-found pages.
    – Zizouz212
    Commented Oct 4, 2015 at 17:37
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    @Zizouz212, perhaps they got a dispensation for this use.
    – vonbrand
    Commented Oct 9, 2015 at 22:54

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