Earlier this year marked the 40th anniversary of the first mass marketing email. Conceptualised on 3 May 1978, marketing emails initially were essentially spam. Email marketing is now the most effective digital marketing channel for businesses across all industries. In fact, the channel was responsible for 20 percent of the average business’s revenue in 2017, according to a Relevancy Group study conducted with OneSpot. Meanwhile, more than a third of consumers have opened separate email accounts solely for brand communications.