NFC technology allows contactless communication between devices like smartphones. It can be used for tasks like unlocking cars, accessing buildings, making payments from a phone instead of a wallet, and sharing content with friends by tapping phones. Proximity marketing uses Bluetooth to target nearby mobile users and deliver content like ringtones or files. Mobile app development considers the variety of phone specifications and allows customizing apps for different platforms and devices. iAds provide interactivity within mobile apps to generate revenue and compensate developers for free apps. Globally over 5 billion people own mobile phones but only around 1 billion are smartphones, with market penetration rates varying widely by country.