1. A method performed by a flow network element in a network flow management system, the method comprising: monitoring network flows at a subscriber-level for a plurality of subscribers; exporting flow records associated with the plurality of subscribers, wherein each flow record includes an identification of which one of the plurality of subscribers the flow record belongs; receiving one or more flow policies that were assigned by applying the exported flow records against a plurality of policy rule definitions, wherein each received flow policy identifies an action to take on network parameters associated with one of the plurality of subscribers as a result of violating one or more policy rules; and applying the one or more flow policies, wherein each applied flow policy modifies at least some of the network parameters associated with one of the plurality of subscribers.