In spite of a long literature on online communities and electronic networks, little theoretical work has been done on understanding a recent online phenomenon: "user-generated content" (UGC) platforms. This paper proposes an analytical lens for the study of social dynamics on UGC platforms. Drawing on Bourdieu's concepts of field and capital, we introduce the notion of online cultural field and investigate which characteristics of agents and their contribution behavior produce status distinctions in these fields. These characteristics are then placed in a framework which attempts to address how capital is produced, reproduced and transformed in online cultural fields and how these processes help us understand the evolution of these fields. We briefly review how we will follow this theoretical model with an empirical investigation.