The first commercial spam message was sent in 1994—at least that’s the general consensus. Lawrence Canter and Margaret Siegel had a program written that would post a copy of an advertisement for their law firm’s green card lottery paperwork service to every Usenet news group — about 6,000 of them.
Because of the way the messages were posted, Usenet clients couldn’t filter out duplicate copies, and users saw a copy of the same message in every group. At the time, commercial use of internet resources was rare (it had only recently become legal) and access to Usenet was expensive. Users considered these commercial-seeming messages to be crass—not only did they take up their time, but they also cost them money.
In reaction to the “green card” incident, Arnt Gulbrandsen created the concept of a “cancelbot,” which compared the content of messages to a list of known “spam” messages and then, masquerading as the original sender, sent a special kind of message to “cancel” the original message, hiding and deleting it. Two months after the original spam postings, Canter and Siegel did it again — upon which the combined load of spam and cancel messages crashed many Usenet servers. Anti-spam measures, it seems, had themselves become spam.
