I want to back this right now. I'm the creator of a mobile payments startup much in the same vein as Venmo. The "killer" app, IMO, is the ability to simply tap two devices together, enter an amount & pin, and ... profit! The problem is I just can't see the adoption beyond closed, corporate applications. What Square has going for it is only the payment-accepting party needs to acquire the dongle. This is a captive audience and very incentivized to adopt. No sweat. But with FloJack you're asking the general public to acquire your dongle with little incentive. Tough. I can't think of anything, but is there a possibility of only one side needing the dongle to participate (the service provider - in my case - someone receiving payment) in a transaction? Convince me otherwise and I'll be happy to back. I'm also happy to discuss details off HN.