When people refer to me on stackexchange websites they call me @H2ONaCl. Where did this convention arise from? If it were taken from my email address, the @ symbol would be at the other end of my name so that does not appear to be the source of this convention.

  • 7
    it comes from Twitter
    – nohat
    Commented Sep 20, 2011 at 23:48
  • 4
    Not really a ELU question: It is a programming convention to ensure that comments can be directed to you by including @broiyan in the text of the comment. You should get a notification that you have "inbox" items in the upper left corner where it says "StackExchange".
    – JeffSahol
    Commented Sep 21, 2011 at 1:03
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    @JeffSahol I think it is an ELU question; I've seen it used in emails and on forums where it's a style thing not a programming thing.
    – Hugo
    Commented Sep 21, 2011 at 6:16
  • 1
    You may be interested in other modern uses of the @ sign. While Twitter popularized the @name convention, it is sometimes used in emails or other contexts where it has no technical effect (it does not trigger a notification but merely serves as a typographical cue).
    – aedia λ
    Commented Sep 21, 2011 at 18:27
  • 2
    This question appears to be off-topic because it is more about technology, not English language. Commented Jan 16, 2014 at 14:07

3 Answers 3


Its first popular use seems to have begun on Twitter. It was formalized on Stack Overflow in January 2010. http://blog.stackoverflow.com/2010/01/new-improved-comments-with-reply/

  • Imagine if Twitter earnt royalties for every @-mention and hashtag!
    – Dog Lover
    Commented Jul 11, 2017 at 4:24

Old IRC (internet realyed chat) services used to offer features that would indicate (in a different color or graphic effect) that a particular message - among tens or hundreds in a crowded chat room - was directed to you or someone in particular. Old school programmers kept the use of it as a way to directly say something to someone in particular. The use of it in Twitter is a re-introduction of this practice.

More and more, even on applications that won't offer any particular effect to respond the existence of the @name convention, people is using it to diferentiate the destination of the message. Like:

@Hugo: it may be now a ELU question, but yes, it is a programmer's thing @aedia: totally agree with you.

  • 3
    It’s the vocative particle, like how in “O Zeus, how mighty are your thunderbolts”, the “O” is the vocative particle. We now use @Zeus instead for the same thing: to summon his attention in our hubris. Apparently Irish does the same thing with an A instead of an O, and an @ is a stylized A. Still vocative.
    – tchrist
    Commented Jan 16, 2014 at 4:02
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    @AtilaTini: It's not just a programmer thing. You used it twice in your answer as a style thing to address different people. No programming parsed it as anything special special in your answer. Plenty of non-programmers now use it everyday.
    – Hugo
    Commented Jan 16, 2014 at 8:05
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    @tchrist: From now on, I'm going to start reading these @s as Os in my head :) Maybe I'll make a Chrome extension to replace them (with an optional "(how mighty are your thunderbolts)").
    – Hugo
    Commented Jan 16, 2014 at 8:07

When the standard "ASCII" TTY character set of 63 printable elements was laid out (by engineers, not linguists) ca 1960, there were several character positions left unassigned, and so somewhat random picks were used to fill them in. "@" was one of those characters chosen.

And once the "@" character thus became available it was, since it had relatively little use in (pre-existing) standard English texts, often adopted to have computer-related meanings, such as the separator in an email address.

As to why the designers of Stack Exchange chose that specific character it's hard to say (ask them!), other than it was "available", and the "at" connotation (plus the association with email addresses) fit fairly well.

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