In this paper, we describe and analyze two of the most popular mobile services platforms, Nokia Ovi and Apple App Store. Analyses of these platforms are based on the IISI n model, that is, the model for ICT Intensive Service Innovations in many-sided markets. In addition to the actual mobile service platforms, we look at the networked market users of these platforms, focusing on the consumers and the application developers. We identify the key similarities and differences in the technologies used, the platform users, and business models. Based on our analyses, we discuss some possible rationalizations for the success and the challenges of these two competing mobile service platforms.