Cell statistics compares the value of the cell it is processing with other layers values in the same location. By using and shift function, you can place the surrounding 8 cells "under" the center cell and do some comparisons that you couldn't do otherwise. For example, if you wanted to know if the grid (pixel) were isolated and surrounded by cells that all had the same value, you could use con() to test if the values of the surrounding cells all equaled their average and if the cell had a different value than the average.
I'm sure there are other SA functions that could do this or something like it more eloquently. If not, this might be a way to attack the problems.
Cheers!