This paper studies communication patterns in mobile applications. Our analysis shows that 65% of the HTTP, socket, and RPC communication in top-popular Android applications from Google Play have no effect on the user-observable application functionality. We present a static analysis that is able to detect non-essential communication with 84%-90% precision and 63%-64% recall, depending on whether advertisement content is interpreted as essential or not. We use our technique to analyze the 500 top-popular Android applications from Google Play and determine that more than 80% of the connection statements in these applications are non-essential