“The Accidental History of the @ Symbol”
“Tomlinson’s challenge was how to address a message created by one person and sent through Arpanet to someone at a different computer. The address needed an individual’s name, he reasoned, as well as the name of the computer, which might service many users. And the symbol separating those two address elements could not already be widely used in programs and operating systems, lest computers be confused.
Tomlinson’s eyes fell on @, poised above “P” on his Model 33 teletype. “I was mostly looking for a symbol that wasn’t used much,” he told Smithsonian. “And there weren’t a lot of options — an exclamation point or a comma. I could have used an equal sign, but that wouldn’t have made much sense.” Tomlinson chose @ — “probably saving it from going the way of the ‘cent’ sign on computer keyboards,” he says.”