1. A wireless end-user device, comprising: a wireless wide area network (WWAN) modem to receive and transmit Internet data between the device and at least one WWAN when configured for and connected to the at least one WWAN; a wireless local area network (WLAN) modem to receive and transmit Internet data between the device and at least one WLAN when configured for and connected to the at least one WLAN; and one or more processors configured to apply a stored WWAN differential traffic control policy to Internet data service provided using the WWAN modem and the at least one WWAN, and indicate to a particular application, via an application program interface (API), one or more network access conditions based on the applied WWAN differential traffic control policy, wherein the one or more network access conditions includes a network access condition that indicates the unavailability to the particular application of an Internet data service that is currently available via the WWAN modem to a different application, but that is indicated as unavailable to the particular application.