Both Canon S100 and Canon N Facebook ready have 12.0 MP resolution sensors but Canon S100's sensor is 1/1.7-inch (7.44 x 5.58 mm ) and Canon N Facebook ready's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Canon S100's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon N Facebook ready.
Below you can see the S100 and N Facebook ready sensor size comparison.
As seen above, Canon S100 has a 1.5x Larger sensor area than Canon N Facebook ready. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.