Oh, this technique is a hidden gem. Should an already existing smoke clone get hit/struck, the smoke which will be spreading from the impact will be used to create other (up to 5) clones, which can use smoke related techniques and normal Tai/Ken I believe (?). It's a good technique to ruin the opponent's plan if he intends to get rid of clones, as this will make his matter worse by multipling the clones in the field. Personally, I'd most likely use this technique to pull an Uzumaki Barrage like technique just for the fun of it.