Would you like a free coffee?

Jonathan Stark is the author of "Building iPhone Apps with HTML, CSS, and JavaScript". These days he made an interesting experiment: if you go to this page and do as the follows:  

1. Save this picture on your smartphone:
2. Go to a Starbucks
3. Order a coffee.
4. Hold the picture in front of the barcode scanner.
5. If there is enough money on my card, the POS will beep and your coffee will be paid for.

It is true. Jonathan Stark uploaded his card information and pay 30 dollar to offer someone a free cup of coffee. If you follow his twitter, you will see how the balance of the card changes. He welcomes everyone to tweet the picture of coffee, the Starbucks location, and receipt. He also shows how to give others a coffee. You may wonder is there any fool would like to pay for other's coffee? Well, after one day, Jonathan found the money in his card increased. Does that mean this game can last longer than we think?

In my opinion, if any drink or fast food company would like to open a account to allow all the consumers to charge and use, this would be a good advertising way. FREE is attractive for many people, and the company may develop relative promotion activities like coupons, membership credits or gifts to encourage charge the account and purchasing the product, brand awareness, interest and even loyalty will be achieved.

If Starbucks get successful because of Jonathan's game, who would like to be the next one to buy you a coffee or something else?