Your key chain just got lighter, your wallet thinner. The hassle of carrying around all those reward cards is over. They can now all be put in your phone.
The free "Google Wallet" app is what's trending today.
It just updated a card scanning feature for your favorite store's cards so when you go to the store instead of searching through your key chain or wallet for the right card, you just pull up the app on your phone and it will be ready to scan.
The app also sends you notifications if one of your favorite stores is having a special promotion or sale.