1. A method for tracking usage of applications on a mobile device, the method comprising: storing, in a rules dictionary, a rule for each application of a plurality of applications that are executable on a mobile device, where each rule for an application comprises an identifier for the application and a regular expression that operates on network traffic caused by executing the application on the mobile device; installing a new mobile application on the mobile device; executing the new application on the mobile device to cause the new application to create network traffic; inspecting the network traffic caused by the new application; creating a regular expression that matched the network traffic created by the new application; and storing in the rules dictionary a new rule that comprises the regular expression created for the new application and an identifier for the new application.