1. A method for monitoring user application activity on mobile devices in a mobile data network in order to provide a report to an operator, the method comprising: receiving substantially all data communications from a plurality of routers in a mobile operator data network, the data communications originating from the mobile devices; filtering the data communications to remove network management traffic and to identify application-level data; inspecting the filtered data communications to detect source IP addresses associated with the data communications; correlating the detected source IP addresses with phone numbers of the mobile devices; detecting events in the data communications caused by the user application activity on the mobile devices; augmenting each detected event to satisfy a set of predefined report criteria by: querying carrier information associated with a mobile device that caused an event, using at least one of the detected source IP address and the phone number, to identify at least one of a location of the mobile device, content of a site requested by the mobile device, and demographics associated with the mobile device; tracking session state information of the mobile device that caused the event using the detected source IP address and the phone number; computing, using the session state information, at least one of how much time was spent in connection with the detected event and data consumed in connection with the detected event.