Why is my iPhone taking up so much memory?

I have an iPhone 16 gb with no music, and almost no apps (instagram and twitter, and I doubt that those are taking up all my memory). I don't have much photos and videos and I'm down to 1.1 gb.

Anything stored on the iPhone takes up memory space… Won't have too much of an impact on the device's available memory, but not many users add just one.