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The First Email: A Message Not Worth Reading

Zusammenfassung

In late 1971, Ray Tomlinson sent the first network email — a message from one computer to another across the ARPANET, using the @ symbol to separate user name from host machine. He sent it to himself. The content was probably “QWERTYUIOP” or something similar — he remembered it as “the first email not worth reading.” The invention of network email was, by Tomlinson’s own assessment, something he did on the side because it seemed like a neat idea, without any awareness that it would become the dominant communication medium of the next fifty years.

The Two Machines in the Same Room

Tomlinson was a software engineer at BBN Technologies (Bolt Beranek and Newman), the Cambridge, Massachusetts firm that had built the original ARPANET Interface Message Processors — the IMP hardware that connected the first ARPANET nodes. In late 1971, BBN had two PDP-10 computers connected to the ARPANET, sitting next to each other in the same room.

Before Tomlinson’s modification, the ARPANET had a messaging capability called SNDMSG — a program that allowed users on the same machine to leave messages in each other’s mailboxes, files in the local file system. It was intra-machine mail only. Tomlinson combined SNDMSG with a file transfer protocol called CPYNET to create a version that could deposit a message in a mailbox on a different machine entirely — any machine on the ARPANET.

The first test was a message from one of the two BBN PDP-10s to the other. The machines were physically adjacent; the message traveled across the ARPANET anyway. Tomlinson later said he could not remember the exact content — “something like QWERTYUIOP” — and called it “the first email not worth reading.”

The @ Symbol

Tomlinson needed a separator to distinguish the username from the destination machine. The separator had to be a character that appeared in no one’s name — otherwise it could be confused with part of the username. He chose @, the “commercial at” sign, which appeared on the keyboard but had no use in SNDMSG or in usernames.

The choice was not the result of extended deliberation. Tomlinson scanned the available symbols, determined that @ was unambiguous and unlikely to appear in a personal name, and used it. The format user@host was so self-evidently correct that no one proposed an alternative. It became the universal convention for electronic addresses and, eventually, for social media handles and everything else that requires distinguishing a name from a context.

The full story of email’s development — including the emergence of SMTP, MIME attachments, spam, Hotmail, and Gmail’s disruption of storage limits — is covered in Email: The Killer App.

What the ARPANET Was For

The ARPANET was a research network funded by the Defense Advanced Research Projects Agency (DARPA) and designed primarily for resource sharing — allowing researchers at one institution to use computing resources at another. The original vision, articulated by J.C.R. Licklider, was a network of machines through which researchers could access programs, data, and computational power regardless of physical location.

Email was not in the original design. Tomlinson invented it as an unofficial side project — a use case nobody had specified, built because it was technically possible with the existing infrastructure. By 1973, a study by ARPA found that email accounted for approximately 75% of all ARPANET traffic. The resource-sharing network had been repurposed into a communication medium almost immediately after email appeared on it.

This pattern — a technology platform being taken over by a communication use case its designers had not prioritized — would repeat with the World Wide Web, mobile phones, and social networks. The lesson of ARPANET email is that communication is almost always the dominant use case of any sufficiently connected network.

Tomlinson’s Assessment

Tomlinson gave few interviews before his death in 2016, and consistently downplayed the invention’s significance from his personal perspective. He described it as a “neat hack” that he had done because he could, not because he saw its future importance. He was inducted into the Internet Hall of Fame in 2012, and earlier received the IEEE Internet Award (2004, with Dave Crocker) and the Prince of Asturias Award for Technical and Scientific Research (2009, shared with Martin Cooper). He died of a heart attack on March 5, 2016, at the age of 74.

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