Men are silhouetted against a video screen with a Twitter logo as they pose with Samsung S3 and S4 smartphones in this photo illustration taken in the central Bosnian town of Zenica on August 14, 2013. Twitter Inc has confidentially submitted a filing with the U.S. Securities and Exchange Commission ahead of a planned initial public offering, the company said September 12, 2013 in a tweet. REUTERS/Dado Ruvic/Files (BOSNIA AND HERZEGOVINA – Tags: BUSINESS TELECOMS)
