This user on Ask Different appears to have no name due to invisible Unicode characters:

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he's the #2 user on the site:

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Why is that allowed? I think it is confusing for users, e.g. when they will see at the bottom of an answer:

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It's not clear who answered, not clear what the rep numbers and badges are related to, and not clear how you can @reply to that user in the comments!

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    @Bart I understand how it works, I'm actually questioning why U+034F ͏COMBINING GRAPHEME JOINER is allowed as a “character” in usernames
    – F'x
    Sep 10, 2013 at 8:37
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    Yup; I'm sure @ShaWizDowArd knows that; he's just posting that because it was someone else recently who was taken aback by a user with such a name. Sep 10, 2013 at 8:43
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    @AndrewBarber that's the same user actually. Guess he's laughing his invisible a$$ off now seeing all the havoc he's causing. Sep 10, 2013 at 8:44
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    @ShaWizDowArd Ahh... well, how could I know it was the same user... since I can't see his name, and all!?!?!?! ;) Sep 10, 2013 at 8:45
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    @AndrewBarber reputation, to begin with... ;) Sep 10, 2013 at 8:45
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    @ShaWizDowArd Next you'll tell me the user ID. Pshaw! Sep 10, 2013 at 8:46
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    User IDs @AndrewBarber ... geez, who voted for you in the elec...ah..nevermind.
    – Bart
    Sep 10, 2013 at 8:46
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    how can i do that. Alt+255 doesn't work.
    – SoWhat
    Sep 10, 2013 at 8:52
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    Because it's hilarious.
    – a cat
    Sep 10, 2013 at 9:29
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    Interesting, it also eats the link to the user account. Maybe we could show a placeholder in such instances? I propose "Keyser Söze". Sep 10, 2013 at 9:58
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    Funny how of all people this question had to be asked by someone who himself is unpingable in chat. Jealousy? Alter ego? BRB posting on Skeptics.
    – ЯegDwight
    Sep 10, 2013 at 12:23
  • @ЯegDwight I am not unpingable anymore :(
    – F'x
    Sep 10, 2013 at 12:39
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    I found this thread because I came across that user on SU today. Not only are they using a non-displaying character for their name, but they are using a blank avatar as well (an 80x80 black PNG set to transparent). While it seems clever (and was probably what they were trying to do), it also seems like a pointless, meaningless attempt to subvert the system.
    – Synetech
    Sep 22, 2013 at 17:48

1 Answer 1


Because Unicode in general is allowed in order to support multiple languages, and because that character, U+034F ͏COMBINING GRAPHEME JOINER, is not tagged as "white space" in the Unicode database.

It would need some additional work to enumerate all the non-visible non-whitespace characters and ensure that the input validation also rejects strings that contain no visible characters.

Unicode doesn't have a "visible" property, otherwise this would be easy.

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    As usual, huge oversight of those who created Unicode, releasing a monster into the wild, without proper constraints. ;) Nov 14, 2022 at 10:42

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