This paper offers an integrative review of how customer loyalty is conceptualized, cultivated, and measured under conditions of digital saturation. It argues that the dominant managerial reflex of stacking points and discounts rests on an outdated, transaction-centred view of loyalty that recent evidence no longer supports. Synthesizing two large meta-analyses and the foundational conceptual literature, the paper distinguishes behavioral from attitudinal loyalty and shows that affective and relational drivers, rather than cognitive incentives such as price and assortment, increasingly account for durable loyalty, particularly in online and hedonic contexts. It then examines personalization as the principal mechanism through which firms attempt to convert data into attachment, and identifies the personalization–privacy paradox as the central tension constraining that strategy. Four widely cited programs are analysed as contrasting archetypes to illustrate how technology, emotion, and value interact in practice. The paper closes by setting out the unresolved tensions, selection effects in program evaluation, the fragility of self-reported metrics, and the ethics of data use, and proposes an agenda for future research. The contribution is conceptual: a consolidated account of why loyalty has shifted from what customers do to how they feel.