I've usually found working on my 12" PowerBook very comfortable, but recently I've started to feel that my posture is beginning to deteriorate. I already use an external keyboard and mouse at work, so I felt that raising the screen up higher would help me to keep my shoulders back and my back in a more natural position. I could have gone the DIY route and propped my laptop up on a couple of phone directories, but I decided to do it properly and get a Griffin iCurve.