The first mass unsolicited email arose from a hardware launch promotion

Evidence

In May 1978, Gary Thuerk, a marketing manager at the Digital Equipment Corporation (DEC), was thinking of a way to publicize the launch of a new line of advanced computers, the VAX T-series. DEC was based in Massachusetts, but Thuerk wanted to gain the attention of West Coast techies as well. So he decided to stage demonstrations in Los Angeles and Silicon Valley. But how would he get people to come? — Tim Wu, The Attention Merchants, 657