I'm planning on making a simple discussion feature for a web framework I'm building. It should:

  • allow anonymous posting
  • block spam bots

The obvious answer is to use a generic "captcha" plugin, however I think there are some creative opportunities here that I would like to explore, e.g. questions like:

  • (simple math) what is four + three? _
  • (pop culture) who sings like a virgin? _
  • (history) last name of first U.S. president: ___
  • (pictures) [picture of Obama], who is this?: ____
  • (contextual) what year was our association founded? ___
  • (company) last name of our personnel director: ____
  • (current events) the country that toppled Muburak: _

The captcha could actually be used to teach people about the community, information that they had to look up, etc.

Or these could be collected from users of the community, the ones which got approved and used would earn them reputation points.

What is the best way for a CAPTCHA to be designed so that it not only blocks spammers but helps reflect the knowledge of a community?

  • Please check the FAQ and Good Subjective, Bad Subjective blog post to learn what makes a good question. This is simply a "list of X" type question. If it could be rephrased then it might make a good question.
    – ChrisF
    Feb 24, 2011 at 9:43
  • that link is broken Feb 24, 2011 at 9:46
  • Assuming you mean the blog link - I've just tried it and it works OK for me.
    – ChrisF
    Feb 24, 2011 at 10:14

1 Answer 1


A variation of the following, at a site of a research institute. enter image description here

Rather simple actually, when you think about it, but guaranteed to scare off most.

  • And what is the answer? :) Feb 24, 2011 at 9:45
  • @Sebastien Le Callonnec - Now that would be telling ;)
    – Rook
    Feb 24, 2011 at 9:48
  • @Sebastien I think it is 0
    – Gaurav
    Feb 24, 2011 at 9:50
  • @Gaurav - Yes. [obligatory remaining characters]
    – Rook
    Feb 24, 2011 at 10:15

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