Based on the literature, a taxonomy of empirical studies that investigate online music systems is discussed in this paper. The studies presented discuss a number of related issues such as music sharing, security technologies like digital rights management (DRM), and changing business models. Research into online music systems is inherently cross disciplinary, and two main groups (industry/users) are identified to classify the research. The PhD research that this paper is based on has a user focus, however it is important to explore related groups and issues in order to adequately investigate. Therefore the taxonomy presented in this paper is significant as it provides an informative base from which to conduct further empirical studies into online music systems. To put the taxonomy into context, details of a current ethnography of online music systems is discussed.