Some growers are now using the "FIM technique" as a way to get more growing shoots per each time you top. The strategy involves cutting off 90% of the growing shoot and leaving 10% intact. From that 10%, up to 8 more branches can emerge. This is useful for those growing SCROG style or those wanting lots of clones from a mother plant.
A shows the tradional method of topping: cutting the whole node off cleanly, to induce the stalk to split into two. But diagram B indicates to make the cut below the center of the node, leaving about 10% intact. This is the key, because the vegetation left behind has cells that are rapidly dividing in many different directions. This can lead to as many as EIGHT tops from a single pruning.