This targeted review explores how online extensive reading (OER) platforms, specifically X-Reading, M-Reader, and Google Classroom, can shift learners from passive interaction to affectively engaging reading experiences. Affective engagement, which includes enjoyment, interest, self-confidence, and reduced anxiety, plays a crucial role in language learning but remains underexplored in digital ER contexts. Drawing on 21 peer-reviewed studies published between 2014 and 2025 and retrieved from the Scopus database (see Appendix 1), this review synthesises evidence on how platform features influence learners’ motivation, affective engagement, and reading behaviours. Findings highlight that platforms integrating audio-assisted reading, real-time tracking, personalized content, and social interaction tend to promote learner autonomy and psychological engagement. Nonetheless, short-term evaluations and a lack of validated emotional metrics point to the need for more long-term, affect-driven research. Notably, features such as Reading While Listening and gamified feedback significantly enhance learner motivation. While not originally designed for ER, Google Classroom supports reflective reading when effectively implemented. The study concludes by recommending emotionally responsive platform design and equitable access policies to foster deeper, more sustainable engagement in digital reading environments.