Microsoft (MSFT) is officially launching Office 2013 today. With Home Premium ($100/year) and Business Premium ($150/year) subscriptions providing coverage for 5 PCs to go with mobile and cloud apps, the refresh is Redmond's biggest attempt yet to migrate users away from up-front licenses. Also included is a touch-friendly UI and the default saving of files to SkyDrive. With an operating profit of $3.57B (63% op. margin), the Office division was Microsoft's largest money-maker in the Dec. quarter.