[janusz]

On May 3, 1978, the earliest documented spam (although the term had not yet been coined) was sent as a message advertising the availability of a new model of Digital Equipment Corporation computers sent by Gary Thuerk to 393 recipients on ARPANET.

Reaction from the net community was fiercely negative, but the spam did generate some sales – and a new business method was born

http://scihi.org/spam-rules-internet/