This PhD research investigates how digital social reading platforms shape reading practices through interface design and algorithmic features. Focusing on social cataloguing sites—where readers create lists, review books, and interact rather than upload texts or purchase books—the study compares globally dominant platforms (Goodreads, StoryGraph, Fable) with European language-specific sites (Databáze knih, LovelyBooks). The platform interface is treated as a non-neutral environment where technological affordances, commercial objectives, and cultural assumptions intersect. Interfaces are analysed in their current form and through archived versions, providing a diachronic view of evolving design strategies. Methodologically, the research combines discursive interface analysis with digital nudging, examining how design elements exploit cognitive biases to subtly guide behaviour while raising ethical and power-related questions. Preliminary results indicate that American platforms are more gamified and algorithmically curated, emphasizing goals, challenges, and social comparison, whereas European platforms present reading in a more database-oriented, less prescriptive manner.