Purpose - Most studies pertaining to social tagging focus on one platform or platform type, thus limiting the scope of their findings. The purpose of this paper is to explore social tagging practices across four platforms in relation to cultural products associated with the book Casino Royale, by Ian Fleming.

Design/methodology/approach - A layered and nested case study approach was used to analyse data from four online platforms: Goodreads, Last.fm, WordPress, and public library social discovery platforms. The top-level case study focuses on the book Casino Royale, by Ian Fleming and its derivative products. The analysis of tagging practices in each of the four online platforms is nested within the top-level case study. Casino Royale was conceptualized as a cultural product (the book), its derived products (e.g. movies, theme songs), as well as a keyword in blogs. A qualitative, inductive, and context-specific approach was chosen to identify commonalities in tagging practices across platforms whilst taking into account the uniqueness of each platform.

Findings - The four platforms comprise different communities of users, each platform with its own cultural norms and tagging practices. Traditional access points in the library catalogues focused on the subject, location, and fictitious characters of the book. User-generated content across the four platforms emphasized historical events and periods related to the book, and highlighted more subjective access points, such as recommendations, tone, mood, reaction, and reading experience. Revealing shifts occur in the tags between the original book and its cultural derivatives: Goodreads and library catalogues focus almost exclusively on the book, while Last. fm and WordPress make in addition cross-references to a wider range of different cultural products, including books, movies, and music. The analyses also yield apparent similarities in certain platforms, such as recurring terms, phrasing and composite or multifaceted tags, as well as a strong presence of genre-related terms for the book and music.

Originality/value - The layered and nested case study approach presents a more comprehensive theoretical viewpoint and methodological framework by which to explore the study of user-generated metadata pertaining to a range of related cultural products across a variety of online platforms.