The app works by analyzing pins on a user's board and then providing product recommendations from Zappos based on the pinned image and the accompanying description; mirror a digital personal shopper that produces a wish list of items that this person may like.
Because the app works by simply entering a person's pinterest username, it also becomes a social commerce gifting service which you can use for gift ideas.
Here are my results when I gave it a try. Not exactly a great match but an interesting idea nontheless, similar to Facebook apps that leverage on your social graph and digital footprint to provide customized content to you.
Try it out for yourself here