You can select a business card from your collection and drop it onto your home screen. Then tap the card widget, it will be immediately shown full screen.
You may whip out your business card as a gunman's shots. Anyway you may use this feature at your pleasure.
This is MAYBE the very first step for cards on-the-fly-exchange via NFC.
*Widgets do not have persistence. They may be reset for some reason. In such a case, please re-create it again.
*Special Thanks to Gregg.