Apple EarPods are just the beginning of the improved audio experience on iPhone 5. It’s designed with three microphones: one on the front, one on the back, and one on the bottom. The front and back mics work together to achieve beamforming — a technique that helps iPhone focus on sound from the desired location for clearer audio. New noise-canceling technology reduces background noise. So when you hold iPhone up to your ear in a loud room, you hear what matters most: the voice on the other end.
If you can read english articles, why don't you just google it? And, similiar feature already applied on other phones as above mentioned. But I guess Apple implemented a workaround method(via 3rd mic and direction analysis) to avoid patent war, pretending they're innovative. For user experience, it's the same, noise-cancellation.
Plus: sometimes, marketing team doesn't know what engineers are talking about, so you can only got blurry info on the officail website.