Oh man, this is great! It's perfect for... seeing texts the second they come in? Showing off your cell phone? Watching videos in a horrid orientation? Wait a minute, why is this useful again?
"I have a good cellphone with all these neat features, but I couldn't find a cheap bike mount for it, so I decided to build one of my own! I've just used cardboard, a lot of black extra strong gaffer tape, about ½ meter (~1' 8") of velcro and a piece of sponge that sits on the back, between the handlebar and the bike mount as a shock absorber."