In this paper, we present a comprehensive analysis of real smartphone usage during a 6-month study of real user activity on the Android G1 smartphone. Our goal is to study the high-level characteristics of smartphone usage, and to understand the implications on optimizing smartphones, and their networks. Overall, we present 11 findings that cover general usage behavior, interaction with the battery, power consumption, network activity, frequently-run applications, and modeling usage states. Categories and Subject Descriptors: C.3 [Special-Purpose and Application-Based Systems]: Real-Time and Embedded Systems; C.0 [Computer Systems Organization]: General