With Office Mobile and a SharePoint client on Windows Phone 7, documents can be synced to Windows Live SkyDrive or a SharePoint server. A likely use case is a professional on the go who wants to make a quick edit to a document as part of a collaborative process. It's less likely that a user would want to use the phone to create a new document, particularly a complicated one, but it would at least be possible.
Microsoft describes Office Mobile as great for "lightweight editing," and commenting on documents, but not necessarily for extensive edits, quite similarly to how Microsoft markets Office Web Apps, which Microsoft views as a complement to on-premise Office software rather than a replacement for it.
Certain aspects of complicated Excel files might not be rendered on a WP7 device, but in general "the quality and fidelity of the Excel spreadsheet is way beyond what you see in other [mobile] platforms," says Microsoft group product manager Guy Gilbert. "It just renders in real high fidelity with tables formatted, graphics and charts looking great."
"For the vast majority of cases you will see what you see on the desktop," Bryan says.
While the goal is to make documents viewed on a phone look just like they would on a PC, Microsoft has added in several mobile-focused features that make it easier to navigate documents on these much smaller devices.
For example, Office Mobile automatically figures out what the key parts of a Word document are and creates an outline allowing the user to skip ahead to the parts they want to see, or can highlight where comments in a document are located, and make it easy to switch between charts and tabs in an Excel document.
There are supposedly 750 million users of Office worldwide, and Microsoft is trying to use that vast base like a club over its rivals. Microsoft has argued that Google Apps falls short in the business world because formatting gets stripped out when Microsoft Office documents are imported into Google Docs. In just the same way, Microsoft is arguing that iPhones and Androids can't match Microsoft's rendering of Office documents or the editing and synchronization capabilities.
That doesn't mean competitors can't try, though. No other phones can connect directly to SharePoint "without an app," a key qualification Gilbert and Bryan make.
Microsoft is itself collaborating with Nokia to bring Office Mobile to Symbian-based phones, and could theoretically do the same for iPhones, Androids and BlackBerries.