One of the most compelling aspects of Office 365--aside from its overall value--is that you can access it from virtually anywhere. Because it is delivered from the cloud, the tools and services in Office 365 are not tied to a single PC or device, and data can be accessed from or synced among a desktop PC, the Web, and your smartphone--assuming you have a Windows Phone 7 smartphone.
Microsoft may be trying to create a value proposition to drive adoption of Windows Phone 7 by ensuring it has a uniquely integrated experience for mobile business productivity. But, whether it's because Microsoft is cocky or foolish is irrelevant: The fact remains that Microsoft is missing a prime opportunity to firmly establish Office 365 as the de facto mobile productivity suite, just as Microsoft Office is the dominant productivity suite for PCs.
Yes, it is possible to use the Web-based tools from an iPhone or Android smartphone, or from an iPad or other tablet PC. But, "possible" can be a far stretch from "optimal." What Microsoft needs to do is create Office Mobile 2010 for other mobile platforms.
While Office 365 works just fine from a variety of browsers including Internet Explorer, Firefox, or Safari, the version of Safari in iOS is not supported. When logging in to the Office 365 on an iPhone 4, you get a sort of warning message first. It explains that the browser you are using may not render Office 365 pages properly, and as a result some features may not function properly.
Once logged in, Office 365 appears just as it does on a PC Web browser. Outlook functions as it should, letting you send, receive, compose, and view email messages. The calendar and contacts features of Outlook also work properly.
However, things get derailed a bit if you try to use the other Office 365 tools from an iPhone. Using the Office 365 Beta, I got a message stating "The following URL is not mobile supported" when trying to open the Word, PowerPoint, or OneNote Web apps. Clicking Excel from my iPhone seemed to open the Web app, but all it does is display a red X with the message, "The workbook cannot be opened". But, I also got errors when trying to create files in the Word, PowerPoint, or OneNote apps from my Windows 7 PC (although Excel worked).
The iPad appears not to have the limitations that the iPhone does. Working with Office 365 from the Apple tablet was no different than working with Office 365 from Internet Explorer 9 on Windows 7. So, at least in that respect Office 365 seems to be functional on mobile device other than Windows Phone 7.
Even if all that is ironed out and you can technically use the Office Web Apps from a smartphone, it is not ideal. The thing is, using a Web interface on a mobile device--especially a smartphone--is simply nowhere near as smooth and effective as a well-written app. For a perfect example, try using Facebook from the Safari browser on the iPhone, then use the Facebook app. The difference is night and day.
Office 365 is a formidable rival for Google Apps for Business, and it may fare just fine as is. But, if Microsoft invested its considerable resources to develop native apps for dominant mobile platforms like the iPhone, iPad, and Android smartphones and tablets it could easily dominate mobile productivity rather than just compete.