It is made so that if you have apps installed on your phone that take advantage of it, it will display your loyalty card, tickets, etc. that are associated with that app. Since it just came out, there aren't a ton of apps that support it yet. I installed the Walgreens app, and signed up for a card (I didn't have one yet.), and now when I open Passbook, it shows the barcode for that card. If you choose a default location, the card will pop up when you are nearby, so you don't have to search through your wallet or keyring to get it.
April
I have upgraded my iphone 4S with iOS 6. All seems well. It has installed Passbook as an App, but it doesn't do anything? It has a link to the App store at the bottom, but when it goes there I can't find Passbook. I am in the UK - is it perhaps a U.S thing?
