This thesis investigates how podcast discovery systems shape cultural visibility, listening practices, and the definition of public value within platformised audio environments. Using Podimo, a European podcast-first platform that also offers audiobooks, as a case study, and with comparative reference to Spotify, it explores how recommendation infrastructures that combine algorithmic personalisation and human curation influence which podcasts are surfaced, promoted, or overlooked. The central research question asks how these systems shape what becomes visible to listeners, and what broader cultural and societal dynamics emerge from their underlying platform logics.Methodologically, the study combines a structured walkthrough of the Podimo and Spotify apps with semi-structured interviews conducted with Podimo employees working in user experience (UX), artificial intelligence (AI), and content curation. Drawing on critical platform theory and the concept of listening as a civic practice, the analysis shows that discovery systems often prioritise content that is easily categorised, gains traction early, and aligns with platform performance goals such as retention and conversion. This can make it more challenging for slower-paced, serialised, or emotionally complex podcasts to gain visibility.The findings suggest that discovery design plays a significant role in shaping access, listening behaviour, and perceptions of relevance. While platform teams are attentive to questions of diversity and value, discovery systems are influenced by a range of operational and strategic considerations, both internally and externally. By combining internal perspectives with broader theoretical reflection, the thesis offers a situated analysis of how podcast platforms support or limit different forms of audio content and proposes ways of enhancing inclusive and exploratory listening experiences.