Here are the two questions: (10k only - since both are now deleted)

The titles are exactly the same - down to the letter. They were also posted two minutes apart.

How did this user get past both the duplicate title filter and the 20 minute question rate limit?

  • 13
    Christmas miracle? Dec 14, 2012 at 16:54
  • They're deleted now, so perhaps we will never know. Are you sure they were both from the same account? Dec 14, 2012 at 18:05
  • 2
    @SamIam 10ks, mods, and developers can see deleted posts. And of course you'd need a developer to fix it anyways.
    – Mysticial
    Dec 14, 2012 at 18:06
  • @SamIam Same account.
    – user200500
    Dec 14, 2012 at 18:07
  • He posted, deleted, then reposted?
    – Cole Tobin
    Dec 14, 2012 at 18:58
  • 1
    @ColeJohnson Nope. I see no deletions in the revision histories other than the most recent ones that came after I linked them here.
    – Mysticial
    Dec 14, 2012 at 18:59
  • @Mysticial Is there a rep limit on seeing the revision history for a deleted post?
    – user200500
    Dec 14, 2012 at 19:08
  • Yes, you still need 10k to see revisions. But neither of them are interesting. For both of them, the OP posts the question, it gets closed and then deleted - presumably by people pouring in from meta. For the second one, the Community user adds the duplicate link. But otherwise, that's it.
    – Mysticial
    Dec 14, 2012 at 19:11
  • I've seen hiccups twice or thrice where the system somehow does a double-submit on the user's behalf. The posters had no idea that it had happened -- they just hit the "Post your question" button once. /cc @Asad
    – jscs
    Dec 14, 2012 at 19:27
  • 1
    But they were 2 minutes apart, and the contents of the posts are not identical. (not saying the OP couldn't have ninja edited though)
    – Mysticial
    Dec 14, 2012 at 19:30
  • @Mysticial: I don't recall the exact time spread of the earlier hiccups I've seen, but I believe there were a few minutes between. I can't find the relevant previous Meta question although I think one exists.
    – jscs
    Dec 14, 2012 at 19:37
  • @Mysticial It is interesting that he posted the copy before his question was closed.
    – user200500
    Dec 14, 2012 at 19:38
  • @Asad I suppose he posted the second one with more information in response to the comments on the first one. Of course neither version was a good question, so they both got nuked. But of course is why the server allowed it in the first place.
    – Mysticial
    Dec 14, 2012 at 19:41

1 Answer 1


The secret might be that the OP added a trailing . or some such character which allowed the question to go through, but was stripped from the title automatically. I haven't tested it so far, but this comment indicates the presence of this behavior at least as far back as September '11.

To elaborate, there is an unrelated automatic ASCII-fication of the title that occurs when you submit your question. From what Marc says here, I assume the dupe check occurs on the title as it stands before the removal of characters, so you can add a bunch of garbage characters to make your title temporarily unique.

Needless to say, this is a bug.

  • But this doesn't explain the 20 minute rate limit. So there's definitely a lot more going on here.
    – Mysticial
    Dec 14, 2012 at 18:44
  • @Mysticial I'll try to find it, but I remember someone saying the timestamp for a question is derived from the time on the person's machine. It was on a question about an answer being posted before the question, if you've seen it.
    – user200500
    Dec 14, 2012 at 18:49
  • 1
    That's not possible because the rate-limit is done by ip address. So it has to be enforced on the server-end.
    – Mysticial
    Dec 14, 2012 at 18:50
  • @Mysticial Do you think they might have forgotten to enforce account based throttling as well? A user could just use a VPN to get around it otherwise.
    – user200500
    Dec 14, 2012 at 18:59
  • That's certainly possible. But we'd need a dev to confirm that. And even then, it's a loop-hole that may or may not be worth fixing.
    – Mysticial
    Dec 14, 2012 at 19:00
  • Can this be the reason for unix.stackexchange.com/questions/369370/… and unix.stackexchange.com/questions/105958/…?
    – Barmar
    Jun 6, 2017 at 15:03

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