Fitts’ Law
I found this little tid-bit interesting. Published by Paul Fitts in 1954, Fitts’ law is a model of human movement which predicts the time required to rapidly move to a target area, as a function of the distance to the target and the size of the target. This law can be applied to the movement of the mouse visitors have to perform to get from point A to point B. For instance, the rule can be important to place the content areas in a more usable way to maximize their accessibility and improve click rates.