Basically, Koni's are 1-way adjustable. You can adjust the dampening capability of the shock, which basically controls the rebound of the suspension. When the control knob is at full soft, the rebound of the shock is slowed down, so the suspension feels softer when you hit a bump, because the shock is not stopping the motion as quickly. As you twist the knob towards stiff, it speeds up the rebound control, and so dampens the effects of a bump more quickly, giving a stiffer ride feel.
Not the best explanation, but I think I got the point across.
Not the best explanation, but I think I got the point across.