The Sales Message That Taught the Early Internet to Fear Advertising

On 3 May 1978 Gary Thuerk, a marketing manager at the Digital Equipment Corporation, sent a single message to a long list of users on the ARPANET, the network funded by the United States Department of Defense. The message, typed largely in capital letters, invited recipients on the west coast to demonstrations of a new computer, the DECSYSTEM 20. Accounts differ on how many people received it, and estimates run from a few hundred upward.

The reaction was immediate and mostly hostile. The network had been built for research, and its users worked under an understanding that discouraged commercial use. An official of the Defense Communications Agency is reported to have complained, and the episode is generally described as drawing a rebuke from network officials. Yet Thuerk has said in later interviews that the message produced sales, which is the awkward fact on which the story turns.

That fact explains why the practice outlived the objection. A method that annoys most recipients can still be profitable if a few respond and the cost of reaching the rest is close to zero. When the cost of sending falls toward nothing, the sender has little reason to be selective, while the cost of attention is paid by the people who receive the message.

A method that annoys most recipients can still be profitable if a few respond and the cost of reaching the rest is close to zero.

The word spam came later and, according to the standard account, was borrowed from a Monty Python sketch and applied first to repeated messages on other networks. Thuerk's message is therefore better described as an early example than as the origin of the name.