Just came across this quiz titled. "Do you really know your iPhone?" Unlike other similar trivia which quiz you on history, this one is about iPhone usability. Fun stuff. Questions: 1. How can you tell a 3G iPhone from 3GS without turning it on? 2. Which setting you have to tweak to turn off all cellular data on your phone? 3. What is the fastest way to find an App? ... Tell us your score!