I see spam submissions occasionally on my blog and online forums. Why aren't there any on Stack Overflow?

What does SO use for spam filtering?

(I have been here for a year and haven't seen a single piece of spam.)

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    See this post too meta.stackexchange.com/questions/2765/… Commented Jul 27, 2010 at 19:28
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    Welcome to Meta, Ankit! For a housewarming gift, go to your accounts tab in your profile and click on the disassociate button by your Stack Overflow account. Then click on associate, and you'll get +100 rep here for free!
    – Pops
    Commented Jul 27, 2010 at 19:30
  • It's not free @pop, it comes with a price... some say it's a high price
    – juan
    Commented Jul 27, 2010 at 19:35
  • ooh grt.. I now have +100. @juan what price? is that because of my SO score? Commented Jul 27, 2010 at 19:37
  • Juan was joking about how much time and effort it takes to participate in SO, Meta, &c. Yes, it's because you have >200 rep on SO. You can repeat this process on every site except for SO itself.
    – Pops
    Commented Jul 27, 2010 at 19:58
  • SO (and SE in general) has a moderation system so powerful that all spam and abusive posts are nuked from the orbit in a matter of seconds.
    – SE is dead
    Commented Aug 28, 2016 at 21:28

5 Answers 5


We get spam, but the community cleans it up. There's a "flag" link under the tags in each question and at the bottom of each answer.

  • i do not see even on newest questions list/view. Commented Jul 27, 2010 at 19:29
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    @Ankit: You need 15 reputation to be able to flag a post. Commented Jul 27, 2010 at 19:30
  • what I mean is "i do not see spam questions even on newest questions list/view".. where they appear latest or any change of others to flag it before. Commented Jul 27, 2010 at 19:32
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    @Ankit: Oh, I misunderstood. I guess the ratio of legitimate questions to spam is so high that you don't see it much. I rarely catch spam posts myself, but usually only see them when someone flags for moderator attention. The reason SO gets so little spam might be because it's proven to be ineffective in the past. If we keep deleting it, there's little incentive for spammers to keep posting here. Plus, most spam I see is in the answers not the question, so you won't see it on the front page unless you click through. Commented Jul 27, 2010 at 19:35
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    And once in a while you manage to make a big catch.
    – Gnoupi
    Commented Jul 27, 2010 at 19:41

Users with 10,000 reputation, along with ♦ moderators have the ability to delete posts, unlike some forums where only moderators are allowed to delete/hide posts/topics.

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    10k users can delete questions but not answers. Answers can only be deleted by the user who posted them (of course), by moderators, or by collecting six spam or offensive flags.
    – mmyers
    Commented Jul 27, 2010 at 19:38

I've never come across a spam post normally, only by seeing them in the list of flagged posts, so they're quite rare. There was just one flagged today that was posted yesterday, though, so it does happen


There are active SPAM detection measures in the SO stack, and, as others have noted the SPAM that makes it through is dealt with quickly by the SO community. I'd also like to think that SPAMmers have figured out that we're a community that doesn't respond to their techniques, but I think that would be giving them too much credit.

It's also possible that Chuck Norris Jon Skeet keeps them at bay, though that reasoning is highly suspect because if he were to try, they would never succeed in getting through.

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    Way too much credit. I doubt that most of these people even have a clue which sites they're spamming, let alone what the click-through rates are.
    – Aarobot
    Commented Jul 27, 2010 at 19:40
  • We do block the really persistent ones, probably before they've reached their learning threshold. Commented Jul 27, 2010 at 19:42

I've seen spam once or twice in 4 months. It's rare because spammers don't build up reputation, and that's because spammers only really know how to spam. That in turn means that all spam ends up being effectively flagged on the front page as a significant change (because it's got to be a question or answer) and the large community then spots it and flags it, and a suitably-empowered person deletes it.

Is SO spam-proof? I don't think so. (I've thought of a way of getting around the defenses while writing this answer for example.) But it's a very hard target as there are barriers to entry that keep genuine riff-raff out. Much easier to pick a target with a better risk/reward ratio like Wikipedia…

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    Getting through is only the first hurdle. Surviving for long in the flames is much harder... Commented Jul 27, 2010 at 21:09
  • @Marc: Spammers are made of asbestos (impermeable to flames, potentially bad for the health) so they don't care. What does happen is just that they get squelched extremely rapidly. Commented Jul 30, 2010 at 21:29

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