Attendee Mariusz Trzaska looks at a Microsoft Corp. Surface Tablet... News PhotoCalifornia,Computer,Computer Equipment,Computer Programmer,Computer Software,Development,Electronics Industry,Finance,Horizontal,Looking,Microsoft,North America,Operating System,San Francisco - California,Technology,The Americas,USAPhotographer Collection: Bloomberg 2013 BloombergAttendee Mariusz Trzaska looks at a Microsoft Corp. Surface Tablet during the Microsoft Corp. Build Developers Conference in San Francisco, California, U.S., on Wednesday, June 26, 2013. Facebook Inc. is building an application for Microsoft Corp.'s Windows 8, adding one of the most popular programs still missing from the operating system designed to help Microsoft gain tablet customers. Photographer: David Paul Morris/Bloomberg via Getty Images