When I started data mining the StackOverflow database, I found a surprising number of users had set their birthday in a way that made them 89 years old.

I blogged about it and gave a full list of the 89-year-old users, and here's a few:

And it's not like it was an even distribution - there were much less 80-87 year old users, and no 90 year old users. I'm guessing these users picked a date 89 years ago (so, somewhere about 1920) that has some special significance, but I can't figure out what it might be.

What's so special about year 1920?

  • 5
    Looks like a totally valid question, voting to reopen. Jan 18, 2014 at 21:05
  • Just to deal with 'too localized' argument: those users are probably 'older' now, and they've all, for some reason, chosen the fake birth date '1920'. This question could be forked to ask about the etiquette of giving fake dates in their profiles. Jan 19, 2014 at 13:57
  • @ŁukaszL. indeed, they are four years older. As explained in the answers, they didn't choose random date but the minimum possible date. Jan 19, 2014 at 14:00
  • 3
    I'm voting to close this question as off-topic because in order to become compliant with GDPR, SE has removed everything related to age and birth years from their system, and as such this question is no longer relevant. Oct 2, 2018 at 7:02

3 Answers 3


Actually, I suspect that the "89 year old" users are simply using the oldest date they're allowed to by the system. If you try to set your birth year before 1920, the system will return an error:

Oops! There was a problem updating your profile:

Birthday - must be after 1920/01/01

  • 4
    Interesting - wonder why some users are older then, like stackoverflow.com/users/522 and stackoverflow.com/users/103 ...
    – Brent Ozar
    Jul 4, 2009 at 0:47
  • 3
    That is a good question. Those user IDs are fairly low, so perhaps they signed up and provided their (obviously fake) DOB before the check was in place? Jul 4, 2009 at 0:48
  • 70
    i guess this means my grandfather couldn't participate in stack overflow. this is ageism. i'm gonna get grandpa to file suit.
    – Kip
    Jul 4, 2009 at 1:01
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    Why use 1920 as the check? If people are going to add a fake date of birth then this clearly doesn't stop them and it is not impossible that it might be someone's genuine date of birth. Shouldn't the earliest date be something biologically unprecedented? Jan 19, 2014 at 14:11

This sounds like blatant ageism. How do you know a 90 year old man wouldn't be a useful member of the website!?

  • 89
    That's sexism. What about a 90 year old woman? Jul 5, 2009 at 3:12
  • 63
    That's speciesism. What about sentient dogs, cats, and hemaphroditic extra-planetary aliens? Jul 9, 2009 at 14:30
  • 60
    That's living-creaturism. What about rocks?
    – çağdaş
    Jul 20, 2009 at 17:02
  • 54
    That's matter-ism. What about clouds of energy? Dec 9, 2009 at 18:45
  • 63
    That's realism. What about invisible unicorns? Feb 25, 2010 at 18:41
  • 66
    That's conceptualism. What about?
    – balpha StaffMod
    May 30, 2010 at 18:36
  • 5
    24th prime number? that's so beautiful :') May 17, 2013 at 16:13
  • 2
    The jokes are cute, but it's a serious point. May 28, 2013 at 21:08
  • 1
    That's... what.
    – NReilingh
    Jun 9, 2013 at 23:38

Even more aggravating is the fact that we do not allow young users on this site.

Birthday must be before 2002/05/30

I was going to sign my 5 year old up for the site cause he was having some programming problems. I had to tell him to lie about his age. He was not too happy.

  • 25
    There are plenty of his peers posting on meta.
    – Rosinante
    May 30, 2010 at 22:17
  • 2
    5 year old?????
    – MCKapur
    May 19, 2012 at 2:39
  • 1
    Actually, it should be 5 year young. May 28, 2013 at 19:42
  • Exactly. I am actually currently 10, but I signed myself up as 13. Come on, can't the younger generation have something to say?
    – user265551
    Jul 10, 2014 at 13:04
  • 1
    @SmallDeveloper, it could be caused by the Children's Online Privacy Protection Rule: "COPPA imposes certain requirements on operators of websites or online services directed to children under 13 years of age, and on operators of other websites or online services that have actual knowledge that they are collecting personal information online from a child under 13 years of age". Jul 13, 2014 at 0:43
  • Yeah, OK, blah, blah, rules, rules, rules
    – user265551
    Aug 17, 2014 at 9:54
  • @Earlz, Instead of a plain "NO", there should be a link to a page describing what must be done for the poor child below 13 to sign up without lying about his age.
    – Pacerier
    Apr 26, 2015 at 13:49

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