This document discusses competition on mobile application markets. It describes how mobile application stores operate as platforms, connecting app developers and users in two-sided markets. The growth of these markets is driven by network effects that increase the value of the platform as more users and developers participate. The document outlines the current state of the iOS and Android markets and opportunities/challenges for different players like platform vendors, smartphone manufacturers, and app developers. It concludes that competition will increasingly focus on software, user experience, and contextual mobile apps that provide new opportunities for developers.