A Whatsapp App logo is seen behind a Samsung Galaxy S4 phone that is logged on to Facebook in the central Bosnian town of Zenica

A Whatsapp App logo is seen behind a Samsung Galaxy S4 phone that is logged on to Facebook in the central Bosnian town of Zenica, February 20, 2014. Facebook Inc will buy fast-growing mobile-messaging startup WhatsApp for $19 billion in cash and stock in a landmark deal that places the world’s largest social network closer to the heart of mobile communications and may bring younger users into the fold. REUTERS/Dado Ruvic (BOSNIA AND HERZEGOVINA – Tags: BUSINESS)