The First Spam Email Was Sent in 1978 — and People Were Furious

ARPANET in 1978 was a small, closely knit community. The network connected about 2,600 users at research institutions, universities, and military contractors across the United States. These users knew each other, at least by reputation, and the network's culture was explicitly cooperative and non-commercial. ARPANET's guidelines explicitly prohibited using the network for commercial purposes — it was funded by the Department of Defense for research, not for advertising.

Gary Thuerk was a marketing manager at Digital Equipment Corporation (DEC), a major minicomputer manufacturer. He had been assigned to promote a new line of DEC computers — the DECSYSTEM-20 — and had noticed that many of the users on ARPANET were exactly the kind of researchers and technical professionals who might be interested in buying one. He decided to send them all an invitation to attend two product demonstrations on the West Coast.

The Message and Its Reception

Thuerk's email was sent on May 3, 1978, to every ARPANET address he could gather for the West Coast region — 393 recipients. The message was straightforward commercial advertising: a notice about upcoming DEC product demonstrations in Los Angeles and San Francisco, with information about the new computers' specifications. Thuerk was clearly proud of his marketing coup and saw it as an innovative use of the new communication medium.

The ARPANET community's response was swift and hostile. The message violated the network's acceptable use policies, consumed network resources, and intruded uninvited into the mailboxes of hundreds of researchers. Several recipients sent angry replies. DEC's account representative received complaints. The message was reported to ARPANET's management, and Thuerk was formally reprimanded and told that such mass commercial advertising was not acceptable.

The reprimand was ineffective in the long run, though Thuerk himself did not send further mass emails. The idea had been demonstrated: a single message could reach hundreds or thousands of people simultaneously at essentially no marginal cost per recipient. The asymmetry between the cost to the sender (near zero) and the cost to the recipients (their time and attention, multiplied by thousands of recipients) made it inevitable that other people would eventually exploit the same opportunity.

The Word "Spam" and Where It Came From

The term "spam" for unsolicited bulk email comes from a Monty Python sketch, performed in the 1970 television show Monty Python's Flying Circus, in which a restaurant menu consists almost entirely of Spam (the canned meat product), with a chorus of Vikings repeatedly singing "Spam, spam, spam, spam" and drowning out all other conversation. The sketch was beloved in the early internet community — much of the internet's early culture was shaped by the same generation that watched Monty Python — and the term was applied, first in Usenet newsgroup contexts in the late 1980s and early 1990s, to messages that crowded out legitimate communication with unwanted repetition.

The term was retrospectively applied to Thuerk's 1978 message once the concept of spam was established, making him "the father of spam" — a title he has accepted with qualified pride, noting that his message generated significant legitimate business interest in DEC's products and could be argued to have been effective advertising.

Spam's Trajectory to Ubiquity

By the early 2000s, spam had grown from an occasional annoyance to a genuine crisis for email infrastructure. Estimates placed spam at 80 to 90 percent of all email traffic during peak periods in the mid-2000s, with billions of messages per day containing fraudulent offers, phishing attacks, malware, and advertising for illegal or dubious products. The economic damage from productivity loss, storage costs, and security incidents ran to billions of dollars annually.

The response was an arms race between spam filtering technology and spam operators. Machine learning spam filters, deployed by email providers from the mid-2000s onward, dramatically improved the filtering of spam from users' inboxes. By the 2020s, while spam still accounts for roughly 45 percent of total email volume, effective filtering means most users rarely see it. The problem was not solved — it was managed, at significant ongoing cost in computing resources and engineering effort.

That management problem traces directly to the afternoon in 1978 when Gary Thuerk looked at ARPANET's directory and saw not a research community but a mailing list.