One of the most common mistakes in email marketing is treating every subscriber as identical — sending the same message to everyone regardless of who they are, where they came from, or what they have expressed interest in. Email segmentation is the practice of dividing a list into groups based on shared characteristics or behaviours and sending tailored messages to each group.
Email segmentation involves grouping subscribers based on criteria such as how they signed up, what content they have engaged with, where they are in the customer journey, their location, or their purchase history. Sending content relevant to each segment — rather than a single message to everyone — typically results in higher engagement, lower unsubscribe rates, and better commercial outcomes. Even simple segmentation, such as distinguishing between new subscribers and existing customers, can meaningfully improve performance.
Segmentation becomes more valuable as an email list grows and more data becomes available about what different subscribers want. Starting with a small number of meaningful segments and expanding as the list develops is more effective than either no segmentation or over-complicating things too early. Our guide to email segmentation covers practical approaches for UK founders at different stages of their email marketing journey.