One card to rule them all
Let's start by making this assumption clear: Cool ideas are only cool if they work. And when your idea has to do with electronic payments, "working" has a whole lot to do with keeping your personal information safe and secure.
But if these guys at Coin have worked that out, they have an incredibly cool idea.
Coin is a plain, grey gizmo that's exactly the dimensions of a credit card, with the magnetic strip on the back and everything. But Coin can act like any of the swipe-able cards in your wallet.
You can store the details for up to eight of your credit cards, or gas station cards, or ATM cards, or gym membership cards or whatever on the Coin itself, with an unlimited number in an app on your smartphone. And when you need that card, Coin will do a perfect impersonation. You can stick it in an ATM. A cashier can swipe it through their reader. If you try to lose it, the smartphone app warns you that you've left it behind. If your smartphone is out of range for too long, the Coin card deactivates itself. You can read more about Coin's form, function and security in their FAQ.
The card will cost $100 when it's made available this summer. For the time being, it's available at $55 ($50 plus $5 shipping) for online preorder. Preorder quantities are limited. That sounds like a pretty good deal, though I'm not sure I've got enough cards in my wallet to make it worthwhile.
But it's a really cool idea.