1. A method of operating a network system, the method comprising: transmitting information to a mobile device, the information instructing the mobile device to configure one or more device agents on the mobile device to apply a first Internet data traffic policy to wireless network Internet data traffic associated with a first category of mobile device applications instantiated on the mobile device, and to apply a second Internet data traffic policy to wireless network Internet data traffic associated with a second category of mobile device applications instantiated on the mobile device, the first and second Internet data traffic policies associated with a wireless network usage data plan associated with the mobile device; and determining whether the one or more device agents on the mobile device are applying the first and second Internet data traffic policies in accordance with the data plan.