WhatsApp, a play on the casual greeting "what's up?", is an ad-free mobile messaging app that allows users to exchange text and media messages through their Internet data plan or through Wi-Fi. Users do not have to pay for SMS. Once you start using WhatsApp to connect with your friends, you'll wonder how you ever lived without it!WhatsApp software automatically compares all the phone numbers from the device's address book with its central database of WhatsApp users to automatically add contacts to the user's WhatsApp contact list.
