If there’s a truism in marketing, it’d be the same as the disclaimer from the old investment firm commercials: past performance is no guarantee of future results. What might have worked yesterday isn’t going to work forever. Even in the days of print-only, marketing campaigns were out-of-date almost as soon as the ink dried; today, we focus on adaptive marketing that can turn on a dime. It’s been a matter of survival for digital marketers from the beginning that they be able to change on the fly – and companies that are still around today are here because they saw how email marketing was changing right as it was happening.

For a little historical context, consider this: the internet itself is only about 25 years old. In the early years, no one outside of universities and research facilities even had an email address. In truth it wasn’t until the late 1990s that email had spread widely enough for marketers to even consider using it as a platform – and the early “wild west” efforts of some of them almost ruined it for everyone.

Once upon a time, it never occurred to anyone that a message in their email inbox wasn’t worth reading; it took years of spam and unqualified “junk” to get to where we are today. Marketers who had once relied upon print mailings — and their associated up-front costs in printing and postage — went a little giddy at the thought of a nearly free vehicle to deliver their messages. But with more enthusiasm than foresight, they went a little overboard.

Physical junk mail already existed, after all; but with the cost of postage and printing out the window, junk email could stack up faster and taller than anyone could’ve imagined. The reason was obvious: it was easier, after all, to just send an email to anyone who had an address, rather than try to weed out people who might not be interested. At first it might’ve seemed like a great strategy that showed results; but as the numbers grew, the predictable result was a lot of people getting really, really annoyed. Eventually the junk email became enough of an inconvenience (and, in the nascent days of dial-up, enough of a measurable slow-down) that developers created the first spam filters. And the rest, as far as email marketing goes, is history.

Modern email marketing has to contend with its own legacy, and is always looking to find ways to transcend the spam filters. Initial efforts went toward trying to “fool” the algorithms, but the result was nothing more than an “arms race” between marketers and anti-spam programmers. Worse still, experts in the newly-emerging field of brand management quickly realized that more damage was being done to a company’s reputation than could ever be overcome by the resulting sales tracked back to an email campaign. So a few of us looked a little harder at the problem.

The “solution” sounded simple enough: only send email marketing to people who were receptive to it. In practice, accomplishing this turns out to be incredibly complicated, and as a strategy it’s necessarily multi-faceted. In addition to crafting messages that satisfy spam filters on servers and individual machines, email marketing today needs to be immediately understood by its audience to be relevant and valuable; when social media is considered, there truly is such a thing as bad publicity.

So what should today’s email marketers take away from an understanding of this history? In a nutshell, it’s this: the importance of reaching the right inbox can’t be overstated. No matter how big or small your campaign, no matter what the message is, if it’s not successfully targeted, it’s as doomed as anything produced by the spammers of the 1990s.

See related article: Do Not Be Fooled Into Thinking That Email Validation Guarantees 100 Percent Deliverability