I love my navigon app on my iPhone 4s, but I have to admit, telling siri to take me somewhere sounds nice. My concern with this, however, is about data usage. Some GPS apps fetch their maps as they need them, over the air. This can be problematic in 2 ways: getting lost in a dead zone and eating up your data plan. FaceTime will likely be a monster on data too. Does anyone here know if there is some sort of exemption on data usage by these apps?