In 1994, Lawrence Canter and Martha Siegel (from the law firm of Canter and Siegel) posted a message on Usenet, offering assistance in getting a U.S. green card. Their offer, being widely distributed to many people who had no interest in getting a green card, was not well received.
They lost their internet service several times, until they found an ISP that did not care what they did. And they wrote a book instructing others how to do what they had done. And the age of commercial spam was born.
Soon after, angry recipients of unwanted email and Usenet messages started referring to the unwanted messages as spam, a reference to the Monty Python skits satirising the well known luncheon meat made by Hormel.
The early spammers were discrete, and obedient. They would end their messages with something like:
I apologise for sending you this without your permission. If you don't want to see any more such email, please let me know, and you won't hear from me again.
And upon receiving an unsubscribe message, they would indeed stop sending email.
One day, the spammers realised that the folks who didn't want their email were not their prospective customers anyway. And further, the time that they spent reading unsubscribe messages, processing those messages, and cleaning their address databases, was wasted time. So they stopped cleaning their databases, and angry recipients were receiving repeated unwanted email, even though they would repeatedly send unsubscribe messages.
The angry recipients found out how to identify the ISPs of the spammers, and started complaining to the ISPs, instead of to the spammers. After some spammers got tired of finding new ISPs periodically, they stopped putting their actual email addresses in their messages. And the modern age of spamming started.
Nowadays spammers spend as much time hiding their activities as actually writing and sending spam. Their current practice is to send spam out thru thousands of hijacked computers, known as botnets. But using a bot for spam distribution, when the computer in question may be in another country or on another continent, is not 100% reliable. So the spammers use redundancy, which is an established practice with computers.
The modern spammer, when sending out a piece of spam to 1,000 victims, will throw a few addresses into the list which come back to him (his personal email, in various services). Knowing how long to wait for email to move, he will wait and make sure that all of his personal mailboxes get their expected copies of his spam. If they don't, he assumes that the spam run just finished was unsuccessful, and he will repeat that run, sending thru a different bot.
Have you ever gotten the same piece of spam twice in 10 minutes or so? This was not a mistake, it was the result of a spam run having been interrupted after you got your copy of spam, the first time. To make sure that the spam gets to everybody, the simplest thing to do is to resend to everybody, and not worry about duplication. So they do just that.
In my next article, Modern Spam, I'll discuss how spam is currently distributed, and how you should and shouldn't deal with it.