Microsoft Office for iOS, Android said to arrive in 2013 -- will this help or hurt Microsoft?

The latest rumors have Microsoft Office launching for iOS and Android early next year. This would certainly help Microsoft on competing tablet and smartphone platforms. But will those gains be offset by the harm done to Windows 8 and RT tablets and Windows Phone 8?

The Verge has what it claims to be a screenshot of Office running on the iPad,and reports that Office will be released for iOS and Android in early 2013. It says that the free version of Office on iOS and Android will only provide the ability to view Office files, but that with a subscription fee for Office 365, you will be able to ability to edit them as well.

This will clearly help Microsoft on competing tablet and smartphone platforms. But it also may harm the company's hopes to gain market share for Windows 8 and RT tablets, and for Windows Phone 8.

Windows RT tablets ship with a free version of Office as does Windows Phone 8. That gives those platforms some competitive advantage over iOS and Android smartphone and tablets. Today, if you want Office on a tablet or smartphone, you've got to buy a device that runs on a platform from Microsoft. But by early next year, if the Verge report is accurate, you'll be able to get Office on a device that runs on competing platforms.

So there's no doubt that releasing Office on iOS or Android will make it somewhat harder for Microsoft to gain tablet or smartphone martket share. But that's more than offset by the gains Microsoft will making by having Office run on iOS and Android.

Windows is no longer Microsoft's main cash cow. Its most recent earnings report shows that the Windows division's net income was down 22% and revenue down 8% compared to a year previous. Its revenue of $3.24 billion trailed the Business Division's revenue of $5.5 billion and the Server and Tools business of $4.55 billion.

Office is part of the Business Division, which is Microsoft's biggest revenue generator. Having Office available on iOS and Android will certainly help increase Microsoft's revenue. And it will do more as well: It will help make sure that people continue to use Office rather than Google Docs or Google Apps. That's more important than the relatively small incremental market share Microsoft may gain by not releasing a version of Office for iOS and Android.

So releasing Office for iOS and Android is a very good move for Microsoft, and a recognition that its future is beyond Windows.