To simplify it even further:
Rocker: the board it pressed upon creation to have a rocking chair bottom. Meaning the pressure is in the center. The benefit is, from the best of my knowledge, that it allows you to press and Ollie easier, as well as helps prevent you from catching and edge when transitioning from edge to edge. A number of park boards are rockered for it's ease of movement.
Camber is the traditional and the exact opposite. The board, when viewed from
The side on a flat surface, will have contact points under the bindings or just outside towards the ends. The benefit of camber is greater control at speed. Although camber may take more getting used to, you have more edge pressure which allows greater stability and pressure. I.e. Less chance of washing out when you've gotta make an "Ohhh Shiii..." stop.
Companies like never summer and others use R/C tech. Rocker in the middle, camber under the bindings. They're like hybrids are to the auto industy. The best of both worlds.
Hope I helped.