"It's your Office. It goes wherever you go," says the short video, which was posted by . When users sign into Office 15, the video says, they can easily pick up where they left off on any device.

As detailed in previous leaks, Office 15 users will be able to sign in to several Web services, including , Flickr, Hotmail, and Windows Live Messenger. There's also a new online service in Office 15 called "My Office," but how that works is still unclear.

Although Office 2010 already allows users to save documents online, the feature is relegated to a separate "Save & Send" menu. As detailed in , Office 15 will have a single menu for offline and online storage locations. With Windows 8, Microsoft will take this a step further by allowing online files to .

Online features are crucial for Office given the competition from Apple and Google. With Apple's , users will be able to save iWork documents directly to iCloud, making them available on the iPhone, iPad, desktop Web browsers, and other Macs. Of course, Google Docs exists primarily online, so users can access their documents in any browser with no extra effort.