Logo of WhatsApp, the popular messaging service bought by Facebook for USD $19 billion, seen on a smartphone February 20, 2014 in New York.   Facebook's deal for the red-hot mobile messaging service WhatsApp is a savvy strategic move for the world's biggest social network, even if the price tag is staggeringly high, analysts say. AFP PHOTO/Stan HONDA / AFP PHOTO / STAN HONDA        (Photo credit should read STAN HONDA/AFP/Getty Images)