Shoe brand Clarks has learned an important lesson about email: It’s not the sexiest of marketing strategies, but it can’t be beat when it comes to cost-effective retention.

The brand’s email strategy, while effective in most cases, was limited in terms of growth potential and reactivity, said Rick Almeida, vp of e-commerce and digital at Clarks. The issues were centered on cart abandonment and online conversion: People were visiting the store’s page, engaging with product and then leaving before making the final purchase.

“The reason we decided to change things up was to improve our ability to grow our loyal customer base and to scale campaigns more easily,” said Almeida. “As we are thinking more holistically about the consumer journey, it’s not just about sending them an email and then another email and another, but rather being more relevant with our data and making it more personalized.”

In response, Clarks, with guidance from marketing technology company BounceX, implemented a new email system with a larger number of behavior triggers. Instead of a generic follow-up email if someone abandons their cart, they can now get a more personalized response based on their specific behaviors on the site.

For example, it now has unique triggers tied to a product left in a cart dropping in price or being close to out of stock, or to browsing actions that may prompt conversion.

“Maybe someone looks like they might be about to add something to the cart — they’re reading a bunch of reviews, clicking through all the photos,” said Kris Mobayeni, avp of marketing at BounceX. “That’s when they need the most encouragement: ’10 people just added it to their carts, why don’t you do it, too?'”

Clarks said that since implementing its new email strategy, traffic from cart abandonment follow-up emails has increased 13 times over, driving 5.5 times more revenue from email.

Clarks’ shift in email strategy comes a year after the brand’s earnings dipped into the red and CEO Mike Shearwood vowed to turn the brand around.

Reactivity and personalization has become a key trend in email marketing. Brands and retailers like TrueFacet and Tumi have all spoken publicly about how cost-effective and efficient email marketing has been for them. And all brands should start paying more attention to their email strategies, said Mobayeni. “Email isn’t that sexy, but marketers know how cost-effective it is, so there’s a lot of competition in the inbox.”

For Almeida, its power lies in the fact that only the most highly engaged and loyal consumers tend to opt-in to it.

“We’ve spent a lot of time in the past few years on unifying data across channels so we can target and segment our audience better,” said Almeida. “It was an important channel for us, and it’s become even more important over time. Email is vital. Customers who opt in and are very much engaged — they’re an important tool. But it’s not just about driving traffic, it needs to be more relevant and timely and be more contextual for the user, or else you risk pushing them away.”