What are some of the automated algorithms used to combat SPAM on Stack Overflow?

The more details the better :)

  • Why, so you can circumvent them?
    – Ether
    Apr 10, 2010 at 15:55
  • 1
    @Ether - No, he's working on Shapado (SO clone in Ruby).
    – Pollyanna
    Apr 10, 2010 at 15:57
  • @Pollyanna - shh, don't tell :) Actually, the "work" I've been doing so far for Shapado is only opening bugs and feature requests ... I'm not one of the developers (yet?)
    – ripper234
    Apr 10, 2010 at 16:02
  • 4
    A team of untouchables: meta.stackexchange.com/questions/46074/… ?
    – Gnoupi
    Apr 10, 2010 at 16:08
  • 1
    Wow, @Gnoupi, I wasn't aware organized crime reached the trilogy. It's a good thing that the powers for good far outweigh the powers for evil here.
    – ripper234
    Apr 10, 2010 at 16:16

4 Answers 4


Much of the noise management is community-driven, by people like you. Inappropriate questions are quickly closed, and outright offensive or spam messages are flagged and deleted from the system when six flags have accumulated. User accounts that consistently spam are deleted.


Q: Are you human?
A: Yes

Not that far from the truth, a CAPTCHA comes up if you're doing "too much too fast".

I also believe magic is involved.


It's unlikely that you'll get much information on this front. While security doesn't depend on secrecy, you don't hand your security plans to the burglars either.

That being said, they haven't done much more than what is considered normal industry practices, customized for the community of spammers SO attracts.

You should be able to get a lot of good information on general strategies and techniques used to prevent spam on Stackoverflow itself:


  • However security by obscurity never leads to a good outcome. The best security systems are those that you can know everything about and STILL not beat.
    – Phoshi
    Apr 10, 2010 at 17:09
  • 1
    @Phoshi - Thus the second sentence in my answer. So many people misunderstand the "security by obscurity" phrase that I knew if I didn't mention it, someone would bring it up. I should have guessed that even if I covered it, someone would still think that it applies to this situation.
    – Pollyanna
    Apr 10, 2010 at 17:24
  • @Phoshi: A spam prevention algorithm isn't really "security." It's more like the playbook of a football team.
    – Aarobot
    Apr 10, 2010 at 18:20
  • Yeah, it's not the right phrase, but I couldn't think of the right one. There's a word I'm sure :(
    – Phoshi
    Apr 10, 2010 at 18:24

Stack Overflow is actually using a human powered algorithm.

Spam management is left to the community who closes and flags problematic posts.

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