NFC (near field communications) technology has been a rumored "upcoming" iPhone feature for quite some time now. It was supposed to turn up in last year's model (obviously it didn't). And of course it's expected in this year's release.
What's the big deal? Well NFC is the backbone of many mobile payment systems. And everyone is waiting for Apple to enter that space. But why wait for NFC, when you can pay wirelessly with your iPhone right now using Square?