There are more than 500 cards in the Storymatic box. They’re color-coded — gold cards have character ideas (“member of the wedding,” “person with a devastating secret”), copper cards have plot ideas or complication, like “nobody will listen” or “this time it’s bound to work.” There are some wild cards too that will mix things up unexpectedly.
The ways an RPG group can use the Storymatic are countless. You could draw some cards to help flesh out the personality and backstory of a new character you’ve just rolled up (this can be a huge boost for your less creative gamer friends, or when you’re just stuck for an idea). GMs can use it to whip up interesting NPCs out of thin air. The plot prompts could even be used to drive adventure writing. We actually used something similar to this recently when creating new Pathfinder characters. We just had a list of character traits that we rolled on randomly, with a system for replacing ones that really disagreed with our character concept. It worked very well, and the Storymatic provides a more elaborate way to go about that.
A lot of the cards reference contemporary things like email or travel agents, which might conflict with a fantasy RPG. You could just redraw those cards, or better yet, creatively adapt them. Email actually refers to a wizard’s Message spell, for instance.
You could probably figure out a way to make the Storymatic into a game itself. It bears a certain resemblance to Nanofictionary in that respect. The right group could easily make an evening of drawing cards and telling stories.
You can check out the official Storymatic website for more info.