Spam is a theft of resources.

And with that, Autumn Tyr-Salvia, Email Strategy & Compliance Analyst from Marketo took us all the way back to the 70s with her talk on the history of email spam at Interact 2013. Here’s a quick timeline:

  • 1978: The first case of spam was recorded where spam was sent to Arpanet address.
  • 1994: On April 12, the first occurrence of major Usenet spam was posted to 5500+ groups with the help of a Perl script.
  • 1996: Bayesian filtering for mail was introduced
  • 2001: Spam Assassin, a rule set developed by Bayesian filtering was added to SourceForge and became the first instance of productizing.
  • 2002: Paul Graham’s Plan for Spam made Bayesian filtering a lot more viable.
  • 2003: US CAN-SPAM came into being. Image spam started.
  • 2004: Spam convictions begin.

The History of Spam

“Spammers check their deliverability as well” 

Image spam, faking headers, phishing, snowshoe spam and URL redirection are all spam techniques that have evolved as a result of filtering. In 2006, Spam Assassin caught over 60% of spam, but in 2007, it caught only 30% of spam.

Whitelisting gave rise to header forging, malware and phishing, which in turn gave rise to better whitelisting techniques, and sender authentication such as SPF and DKIM.

Content filtering initially used simple word blocking lists, but this was easy to avoid with misspellings and punctuation. This led to Bayesian filtering where misspellings became immediate spam words and strange punctuation was problematic. Unintentional, poorly thought out domains and subdomains ran into trouble with filters.

Content filtering eventually evolved to weighting which led to super short messages that received extra attention. Next came domain reputation. Use of URL shorteners increased the possibility of emails being blocked. Spammers started to obtain new domains constantly for spamming. As a result, new domains have reduced deliverability and as a tip, domain consolidation is a good idea for a white hat sender.

At a time when text filters were increasingly effective, spammers hit upon the idea of using image spam. These were hard to filter, hence all image messages became difficult to deliver, while text-to-image ratio became important for deliverability. Image spam further evolved where scripts were created to modify each image slightly and spammers started to use CAPTCHA-like techniques. Today advanced filtering techniques have reduced image spam to 6-7%.

“We’ve made smarter spammers”

Deliverability techniques don’t always make sense in today’s spam landscape and some filtering techniques are effective only for a certain period in time, but knowing more about the history of spa can help you to deliver your mail tomorrow. When asked if we’ve finally beaten spam by a member of the audience, Autumn replied, “We’ve made smarter spammers.”

It’s clear from Autumn’s talk that the history of spam is really that of a never-ending race between spammers and ISPs to stay one step ahead of each other and that looks set to continue for the foreseeable future.

Aside from combating spam, find out what it takes to become a successful email sender with The Six Secrets of Successful Senders Guide!