When the front and back of your popular smartphone is made from glass, you can bet that there will be a bunch of those devices that get shattered in a short drop. Even using Gorilla Glass wasn't enough to prevent buyers of the iPhone 4 from crying foul when the front and back of the smartphone could shatter.
A patent has surfaced that shows that Apple is hard at work creating a smartphone that has glass that won't shatter when you drop it. The patent outlines some interesting stuff that shows how Apple plans to add a sort of buffer behind the glass panels that would allow the glass to give rather than shatter in a drop.
The shock system would separate the glass from the rest of the smartphone. Another method of protecting the glass sounds complex. It involves drop sensors in the phone that would partially retract the glass into the body of the phone when a drop was sensed. We have also seen patent apps in the past that showed a system using airbags to protect the glass. I think the shock isolation system is the most likely candidate for future iPhones.