@SexyToad: Pretty much. But they also have the story bits on them too. They're like the replacement for the book pages to make it easier for multiple people go through the story and take different paths. This is basically the information you would find on a card, except instead of links leading to other pages there would be numbers that point to other cards.
I beginning to realize that maybe this doesn't make quite as much sense to someone who has no experience with the CYOA style of book. Which is good since making the instructions is one of the most important making any game.