Facebook Inc. chief executive officer Mark Zuckerberg said his hardest job right now is figuring out how to adapt the world’s largest social network to mobile devices. Bringing Facebook’s features to hand-held gadgets is difficult because the user experience is so different than on desktop computers, he said in an interview from the Allen & Co. media conference in Sun Valley, Idaho. Zuckerberg, meanwhile, played down the tribulations of running a newly public company. “Things are not much different,” Zuckerberg, who started Facebook eight years ago from his dorm room at Harvard University, said. “I’m focused on building product.” Facebook is under pressure to get more advertising revenue from its mobile service in order to maintain growth. To bolster the hand-held version of its product, the Menlo Park, California- based company is developing location-based features that let marketers target users with more relevant pitches. Concerns about slowing growth have driven down Facebook’s shares 19 per cent since they began trading in May. The stock fell less than 1 per cent to $30.72 at the close today in New York. Zuckerberg was joined at the Allen & Co. event by other technology and media executives, including Apple Inc. CEO Tim Cook, Washington Post Co. chief Don Graham, and venture capitalist and Facebook board member Marc Andreessen. Even with all the additional scrutiny, Facebook’s IPO hasn’t been the biggest recent transition in Zuckerberg’s life, the 28-year-old said in the interview. The same week as Facebook went public, Zuckerberg married longtime girlfriend Priscilla Chan. “The bigger change was getting married,” he said. From gulfnews