Origin of @username in online conversations?

So, how did it arise? I understand why it was used, but not why it ever began.

For example:
Username1 says [something]
[other users comment]
Usernamex says “@Username1, I totally agree!.”

What did the @ sign add that the usual written comma and space after an noun of address didn’t?

Twitter? The @ sign tells Twitter to look for a username and “link” it up to the matching account, creating a hyperlink in the text to the @user’s profile and notifying them that they’ve been mentioned.

I’d be interested to hear if anyone was using that ‘@username’ syntax before that; maybe Twitter didn’t invent it, but it was certainly used for the same purpose. Facebook even got on board with it (after Twitter) so that the @ symbol automatically links to someone’s profile. If you’re seeing it elswhere and it doesn’t create a link to the profile, people are just using it because they’re used to it in the ones that do.

EDIT: I’m not sure I understand what you mean by “I understand why it was used, but not why it began…” So you probably know what it does…so, why? Because it’s a quick way for the app/application/web service to understand what you mean. If you mention “chupacabra” or any other random word, you might literally mean that word. So how’s it supposed to know you really mean the user named “chupacabra”…by using an operator that signifies who you’re talking to. By saying that you’re directing a comment at (’@’) chupacabra, using the “@” operator is a quick way and relatively intuitive way to define what you mean.

The usage definitely predates Twitter; people were doing it on IRC to get a user’s attention back in the 90s. I’m sure Twitter copied the convention from that, or possibly something older.

It’s an abbreviation (or, more correctly, ligature) of at.

Aaaaah! Thank you!

Wait what? You needed an explanation of the “at” ligature? Which has been used in email (and pronounced as the word “at”) since 1972?

TBH, I never would have guessed.

Sacrilege! Everyone knows that e-mail wasn’t invented until 1979, by Shiva Ayyadurai.

We went around this bush a couple years ago.

It turns out the symbol “@” that is fairly widely known in English as the “at symbol” or “at sign” and has done so for 150+ years, doesn’t have that connotation even a little bit in many (most?) European languages.

IIRC the Germans just call it “monkeytail.”

So with no connotation of towards, “@username” to mean “directed at username” is exactly as non-obvious and arbitrary a syntax as “$username” or “)username” would be to an English speaker.

And with no connotation of *location *or *membership *“BobJones@BigCorp.com” doesn’t obviously mean “the Bob Jones who works for BigCorp” any more than “BobJones!BigCorp.com” or “BobJones^BigCorp.com” does.

More and more non-English languages are picking up on the *towards *and *membership *connotations of “@”. But they didn’t have any such meaning as the internet and email first came into being and all this syntax was created of, by, and for Americans plus a few Brits.

Yes, in English it is a symbol for “at” and most importantly, one that was in many standard business typewriter and teletype keyboard layouts for decades, as it was often used to type things such as “compressor delivers 100 psi @ 2000 rpm” so in the old days when every byte would cost you it was available and had an ASCII code early on so it was readily useable in various e-communications to represent location.

In Spanish, the ligature was also used historically as the abbreviation for “arroba”, a unit of a quarter of a hundredweight, and many hispanophone people today say “arroba” when spelling out e-mail addresses.

There are only so many characters in ASCII. Once you remove the alphanumerics and those characters that have other reasonable interpretations, you are not left with many to use for such a designator. !$%&()+=:;"’?/{}<>,. are all easily disqualified. So you really only have ~^`_@#| Even @ is a stretch. But it is a visually good choice.

I would disagree that @ was an arbitrary choice for email. ! notation provided the complete path, not just the username to address separator for UUCP style mail. Sendmail uses # as a comment marker in its configuration file, and uses | < > : for specific purposes, so they would be bad. It wasn’t as if Sendmail was the only answer. X.400 was out there too.

Curiously @ i a symbol that is rarely used in computer languages (there are a few that do) but for many mainstream languages @ is simply illegal anywhere except a string. That makes it rather useful for many text handling tasks, and building template languages. gcc will simply flatly complain that it found an @.

FWIW, I first recall seeing the at-symbol in a Bester novel where a character is referred to as “@kins”.

Bumping this because Ray Tomlinson died two days ago. Whilst not the OP’s answer, he gave us the @ in email, which is very likely part of the answer.

The usage I remember seeing in old documents is in invoices and receipts: for example, “50 lbs winter wheat @ 4¢/lb = $2.00”.

Yeah. In English that goes back to the late 1800s. In other languages, it goes back only as far as the current email addressing system.

Interestingly, all English keyboards have a #(hash) key. I had seen it often enough, but never used it pre internet, when I saw the American usage as ‘number’. We always used No.

Also used in the Americas as a (by now obsolescent) symbol for pounds (weight), apparently derived from the Latin ℔ ligature (if you can’t see the character: lb with a horizontal crossline through the upstrokes). Thus was often referred to as “the pound key” when it appeared on telephone touchtone keyboards. May have fallen out of usage in Brit English before it did over here.

Eh. . . no. . . but thanks for playing.

I believe generally in the US #3 means number 3 while 3# means 3 pounds. The latter however, is falling out of use.

What OldGuy said about #3 vs 3# at least as I’ve always seen the # symbol used.

In United States at least, # is widely known as “the pound symbol” but only rarely used with that meaning. (Was it ever commonly used that way?)

On telephone keypads and similar, it has become common to use this as a sort of “Enter” key, to terminate an entry. (“Please enter your account number and then press the pound key.”)

Useless bit of mildly interesting trivia - on both UK and US layout QWERTY keyboards, Shift-3 produces a symbol known as “pound”. It’s not the same symbol, though. On a UK keyboard Shift-3 produces £.