Occasionally, when I ask a question on some Stack Exchange site, I'll see a page like this wanting to verify whether or not I'm human.

I'm trying to figure out what I am doing that looks suspiciously non-human. How is this page triggered?

(Ironically, when I posted this question, it asked me to do the CAPTCHA.)

  • 13
    Good try, robot.
    – Pekka
    Nov 2, 2011 at 15:54
  • 4
    I'm pretty sure that this won't get an (official) answer. Documenting what makes the system suspicious would make it far too easy to game the system. Nov 2, 2011 at 15:58
  • 2
    I agreed with @Joachim, until I found this question. Its a couple of years old, but will give you an idea of how it works.
    – ughoavgfhw
    Nov 2, 2011 at 16:00
  • 5
    What triggers the CAPTCHA for me every time is if I paste a question or answer into the edit box and then hit "Post" straight away.
    – ChrisF Mod
    Nov 2, 2011 at 16:11
  • 2
    @JoachimSauer If documenting their security measures would make them easy to game, then they have poor security measures, i.e. security through obscurity. Nov 2, 2011 at 17:16
  • 2
    I strongly believe in Kerckhoff's Principle, but there's a difference between making something secure and making it harder for spam bots to waste everybody's time.
    – balpha StaffMod
    Nov 2, 2011 at 17:26

1 Answer 1


In my experience, that page tends to appear when I write my answer in Notepad, for example, then paste the answer into the answer box and then immediately click Post Your Answer.

  • +1 Just because your name is Peter O., like me. Nov 2, 2011 at 19:54

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