Men are silhouetted against a video screen with an Twitter logo as he poses with an Samsung S4 smartphone in this photo illustration taken in the central Bosnian town of Zenica

Men are silhouetted against a video screen with an Twitter logo as he poses with an Samsung S4 smartphone in this photo illustration taken in the central Bosnian town of Zenica, August 14, 2013. REUTERS/Dado Ruvic (BOSNIA AND HERZEGOVINA – Tags: BUSINESS TELECOMS)