This review synthesizes recent research on digital consumer behavior and evaluates the methodological directions likely to shape future inquiry. Using a structured narrative synthesis of 81 sources published mainly between 2020 and 2025, the study examines theoretical frameworks, behavioral drivers, customer journey and loyalty outcomes, and the research designs used across e-commerce, social commerce, mobile shopping, and omnichannel retail. The synthesis shows that trust, perceived risk, review credibility, personalization, and platform design consistently shape purchase intention and engagement, while customer journeys are increasingly non-linear and distributed across touchpoints. Theoretically, the field is moving from narrow technology-adoption models toward trust-, experience-, and journey-centered frameworks. Methodologically, cross-sectional surveys analyzed with structural equation modeling remain dominant, although digital trace data, AI-assisted text analytics, social media mining, and mixed-method designs are expanding. Post-purchase outcomes, channel switching, privacy and ethics, and cross-cultural variation emerge as under-explained areas. The article proposes a three-layer framework that combines perceived, observed, and interpreted behavior, and argues that future research should prioritize longitudinal and panel designs, triangulation between self-reports and behavioral traces, and ethics-aware access to platform data.