Jack Dorsey, interim chief executive officer and co-founder of Twitter Inc., arrives for a morning session during the Allen & Co. Media and Technology Conference in Sun Valley, Idaho, U.S., on Thursday, July 9, 2015. Billionaires, chief executive officers, and leaders from the technology, media, and finance industries gather this week at the Idaho mountain resort conference hosted by investment banking firm Allen & Co. Photographer: David Paul Morris/Bloomberg *** Local Caption *** Jack Dorsey