A plethora of psychological research suggests that gratitude interventions can improve individual well-being and prosocial behavior. However, most of the existing studies focus on gratitude interventions of individuals within controlled lab-based experiments. Our work aims to explore how people practice public gratitude in their everyday lives. This paper presents the design of our public gratitude platform that allows users to freely post gratitude as a tree leaf. Based on usage data spanning 3 years since its launch, our exploratory data analysis provides empirical insights into how people engage in gratitude practices ‘in the wild’. Six types of gratitude, together with their characteristics are identified: personal, work-related groups, study-related groups, gratitude to public service, local community, and event-triggered gratitude. This paper highlights the organic growth of our gratitude platform and its innovative use. Furthermore, the limitations of our work are discussed, shedding light on potential opportunities for future research