1. A wireless end-user device, comprising: a plurality of wireless modems to communicate data related to one or more Internet access activities, the plurality of modems including a wireless wide area network (WWAN) modem to communicate data related to one or more Internet access activities between the device and at least one WWAN, when configured for and connected to the WWAN, and a wireless local area network (WLAN) modem to communicate data related to one or more Internet access activities between the device and at least one WLAN, when configured for and connected to the WLAN; a non-transitory memory to store a network service activity control policy set, the policy set including at least a first differential traffic control policy element indicating whether or not to implement a first selective block to prevent one or more Internet access activities associated with a first end-user application from communicating data over at least one wireless network, and a second differential traffic control policy element indicating whether or not to implement a second selective block to prevent one or more Internet access activities associated with a second end-user application from communicating data over at least one wireless network; and one or more processors configured to implement an application program interface (API) to control application access to Internet data services when data for Internet access activities is communicated through at least one of the modems, the API, when the first differential traffic control policy element indicates the first selective block should be implemented, to selectively block one or more Internet access activities by the first end-user application through one of the plurality of modems, and to selectively allow one or more Internet access activities by the first end-user application through another one of the plurality of modems, and the API, when the second differential traffic control policy element indicates the second selective block should be implemented, to selectively block one or more Internet access activities by the second end-user application through one of the plurality of modems, and to selectively allow one or more Internet access activities by the second end-user application through another one of the plurality of modems.