So I’ve noticed that I call people less (and vice versa) via the default phone app after discovering that the NSA monitors every phone call in the US of A.
I barely called before due the prevalence of so many superior alternatives like video calling (via Google+ Hangouts, FaceTime, etcetera) and messaging (iMessage, Snapchat, App.net, Twitter, et al).
But after the NSA revelations I have (without realizing it) shifted most of my phone calls to strictly business.
My data usage (when iPhone isn’t randomly hoping upon WiFi networks) remains the same however.