THE rise of the smartphone has been a mixed blessing for operators of mobile networks. People have been pleasingly eager to buy smartphones and to clock up data charges by playing games, watching videos and dawdling on social networks, as well as to make calls and send text messages. Yet smartphones have also opened the door to disruptive newcomers. Suppliers of “over the top” (OTT, or “value added”) services have been pinching the network operators’ customers by offering messaging and voice-over-internet-protocol (VOIP) calls via smartphone apps.
