An app which measures your phone's radiation emissions was rejected by Apple, and has redesigned itself for launch on Android. Tawkon, a Tel Aviv start-up, is responsible for the creation of this app, which collects a variety of data regarding which network band a phone is working on, the type of wireless antenna being used, and how hard the phone has to work to get a signal (all things exposed by a smartphone's OS). The app then runs a patent-pending algorithm to determine what rate of radiation absorption a phone user is facing, and how to minimize risk.
It's an interesting bit of technology, and I'm surprised that Apple would reject this type of app. It seems like the creators are primarily concerned with providing information to smartphone users, rather than scaring people out of using smartphones entirely.
I don't know that the long-term effects of radiation exposure through mobile devices have been adequately studied yet, so it's nice to be given more information about what a lot of users see as essentially a magic, hand-held talking box.