Klaviyo, Attentive, and Postscript are renowned for their mass email and SMS campaign capabilities. They cater to diverse customer segments, from entire customer lists to behaviour-based segments like recent web visitors, and are particularly adept at managing flows like cart abandonment reminders.

However, there's a delicate balance to maintain. Frequent emails or texts to a large portion of your opt-in customer list can feel invasive, potentially leading to unsubscribes. This not only affects your immediate campaign success but also the long-term value of the customer relationships you've worked so hard to build. Email and SMS flows are undeniably valuable, aiding in recapturing potential revenue when customers engage with your brand. But remember, this approach is fundamentally reactive, addressing just one side of the customer engagement spectrum.