What does SnapsToDevicePixels in WPF mean in layman terms?

Anybody? Say I have a Window Class and I give SnapsToDevicePixels = true? what happens?

From stackoverflow

• It will enable pixel snapping for every element in your window as this property is inherited by child UI elements. It won't have an effect on the appearance of the window itself, though (i. e. window frame or similar).