I was curious too. Here’s the information from the Blender Manual:
New Options
https://www.blender.org/manual/render/cycles/settings/motion_blur.html
Motion Blur vs. Vector Blur
https://www.blender.org/manual/render/blender_render/settings/motion_blur.html
Example of “Rolling Shutter”:
https://s3.amazonaws.com/pbblogassets/uploads/2015/04/Rolling-Shutter-Featured-Image-865×505.jpg
It would be nice to see some Blender examples of when adjusting the curve is desired, or how to do the Rolling Shutter effect as shown in that photo.