Microsoft on Thursday will publicly webcast a press event from San Francisco during which many expect CEO Satya Nadella to not only make his first appearance but also announce an upcoming Office for Apple's iPad.The event, slated to begin at 10 a.m. PT (1 p.m. ET) and run approximately an hour, will be "focused on the intersection of cloud and mobile computing," according to invitations that went out last week to reporters and industry analysts.