In the past few days (I can't remember when this started, I think around 2011-10-20 give or take a couple of days), I've had far more captchas than usual. I'm getting more than one a day, when until then I'd never get a captcha for posting an answer, only for unusual behavior (like make multiple edits or many comments or cast many votes in quick succession). In each case, I was just posting an answer (or in one case a question), I hadn't done anything unusual or strange.

Today I've had four captcha requests: two on Unix, one on Travel, and one on — I'm not 100% sure now (it was a couple of hours ago), but I think it was French. How many times do I need to prove that I'm not a robot‽


  • And it's not just answers: I was just captchaed for this question, five minutes after being captchaed for an answer on the main site. Oct 27, 2011 at 22:08
  • For reference, this post: meta.stackexchange.com/q/1343 defines the official trigger levels to generate a captcha. Are you triggering at those limits, or do the captchas seem to be appearing at other times? See also meta.stackexchange.com/q/37324. Nov 3, 2011 at 1:13
  • 3
    I know why this is happening ... discussing with the team
    – waffles
    Nov 3, 2011 at 1:14
  • In particular "The minimum window is 5 seconds" was disabled by mistake which caused bots to flood us
    – waffles
    Nov 3, 2011 at 1:15
  • @Kevin I was nowhere near these thresholds. I'd spend at least several minutes composing an answer, then get a captcha when posting. Nov 3, 2011 at 9:57
  • 1
    It started around 2011-11-20? Is this a warning that you are going to start spamming in a couple weeks?
    – ughoavgfhw
    Nov 4, 2011 at 2:38
  • 1
    @ughoavgfhw It was a subtle way of conveying that I'm not a robot: I can't count. (What, I'm not credible? Well, how about this: surely sci-fi has taught you that robots cannot pretend to joke?) Nov 4, 2011 at 8:21

2 Answers 2


Wow, this was an interesting bug ... or series of bugs.

I fixed our anti-bot spam protection a few weeks ago, to great effect. However, there was a separate series of bugs in the code responsible for invoking it in JavaScript. In some cases it was being called twice, causing double the spam protection. Our server side could not handle that doubling of data.

Should be much better now.

FYI I added some rich logging around all captcha invocations, we can do some pretty deep analysis on this, ping me if you notice any weird and misplace captchas.

For the record, if you edit or post an answer real quick (5 seconds) you will still get a CAPTCHA.

  • My impression is that I get captchas mostly when I post real slow...
    – Benjol
    Nov 4, 2011 at 7:54
  • @Benjol I fixed and deployed a serious bug there ... if you take hours to post an answer (from the time you started) you will get a CAPTCHA. If you take less than 5 secs you will as well. Otherwise you should not.
    – waffles
    Nov 4, 2011 at 7:57

I've had this problem on a regular basis, but only on Unix and Linux. It goes in spells, once it thinks I'm a robot it keeps trying to catch me up for a couple of days before it lets me go.

I have had 4 or 5 spells of this on this site but never on other sites. I assume this must have to do with the content of posts triggering higher suspicion weights.

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