[abscr]

Never read it, but I'm guessing it means when you have something like 8c 9s Ts Jc and the flop is 7s 8s Ad, you have two killer cards of 6s and Js along with your other outs against AAxx. If you hit the 6c on the turn, the AAxx can still hit a 6 not of spades,7,8,A to redraw on you. But if you hit the 6s or Js on the turn, the AAxx can't redraw out on you.