Afaik, normal camera sensors acquire the image row by row from top to bottom or vice versa. I forget. So if you are recording video and sweep the camera left to right youll see that vertical lines like telephone poles etc will be staggered (stair-stepped) and have rolling shutter. But with a global shutter the whole sensor is captured at once and not line by line so when you shoot video and pan the camera vertical lines look straight. You can get over this by having the top to bottom scanning time be super fast (and this i think varies from camera model to camera model) or all at once like this new sensor.