Ray Tomlinson

By Nadia El-Masri

The most-used punctuation mark in human history was chosen because it was sitting on the keyboard doing nothing. In 1971, Ray Tomlinson, an engineer at Bolt Beranek and Newman in Cambridge, Massachusetts, the company that built ARPANET's switching computers, was working on two small programs: SNDMSG, which let users of a single time-shared computer leave messages for each other, and CPYNET, which could move files between computers on the network. On a hunch, he combined them, creating a program that could deliver a message from a user on one machine to a mailbox on another. The problem was addressing: how do you name a person on a different computer? Tomlinson needed a separator between the user's name and the host computer's name, a character that would never appear in either. Glancing at the keyboard, he picked @, the commercial 'at' sign, used mainly by accountants. The first address was tomlinson@bbn-tenexa, and the first network email, sent between two machines sitting side by side in his office, was, by his own cheerful admission, utterly forgettable, something like QWERTYUIOP. Born in Amsterdam, New York, in 1941, Tomlinson was a quiet, self-effacing man who never sought fame for what he had done; when asked why he chose @, he said it was simply the only preposition on the keyboard. Email spread through ARPANET like a rumor, and within a few years it was the network's most popular application, the 'killer app' that justified the network's existence to skeptics. The @ sign escaped the laboratory and became a global glyph, pronounced 'at,' 'arobase,' 'snabel-a,' 'kukac,' in dozens of languages, the single character that means a person has an address in the digital world. Tomlinson was inducted into the Internet Hall of Fame and received the IEEE Internet Award; he died of a heart attack in 2016. He never patented the @. It belonged to everyone the moment he typed it. Tomlinson worked for Bolt Beranek and Newman, the Cambridge firm that built the Interface Message Processors, the refrigerator-sized computers that switched ARPANET's packets. His email program ran on the TENEX operating system for the PDP-10, and the first messages traveled between two machines sitting side by side, a demonstration that proved nothing about distance and everything about addressing. The @ sign itself was an old commercial symbol, meaning 'at the rate of' on invoices; Tomlinson repurposed it because it was the only preposition on the keyboard, a piece of typographic luck that made the address readable in plain language: user at host. Within two years, three-quarters of ARPANET traffic was email, a statistic that stunned the network's founders, who had built it for remote computation. Tomlinson never commercialized his invention, never founded a company on it, and seemed faintly bemused by the fame that found him late: induction into the Internet Hall of Fame in 2012, the IEEE Internet Award, and obituaries around the world when he died of a heart attack in 2016. The @ has since acquired names in dozens of languages, from the French 'arobase' to the German 'Klammeraffe,' spider monkey, to the Italian 'chiocciola,' little snail, a small monument to the fact that the whole connected world agreed, without a committee, on one man's keyboard improvisation.

Impact on civilization

Network email was the internet's first proof that connecting computers was about connecting people. Before Tomlinson, a computer network was infrastructure for moving data between machines; after him, it was a medium for human correspondence, and email became the application that made the network indispensable to institutions years before the Web existed. The user@host convention he improvised became the universal grammar of digital identity: every email address, and by descent every social media handle, follows the logic he typed in 1971. Email reshaped office work, collapsing the memo, the letter, and the phone tag into an instantaneous written record, and it created the template for all asynchronous digital communication that followed, from texting to messaging apps. A single keystroke, chosen for convenience, became the addressing system of the connected age. Email's conventions became the conventions of digital life. The inbox, the subject line, the reply, the forward, the attachment: every messaging system since has either copied or deliberately reacted against the grammar Tomlinson established. The address format also solved, almost by accident, the problem of global unique identity; long before usernames and handles, user@host proved that a short string could name a person unambiguously anywhere on earth. Spam, phishing, and the entire email security industry are the shadow of that success, the price of an addressing system designed in an age of trust.