Moves by Apple, Google, and Microsoft demonstrate the rapidly shifting dynamics of the office software space.

Microsoft announced last month that Yammer’s sales had exploded in 2012, shooting up 259 percent year over year (see Microsoft says Yammer sales are booming), vindicating the acquisition of the work media tool by Microsoft earlier in 2012. This is prior to the Microsoft sales team getting its hooks into Yammer and prior to the ongoing integration of Yammer into the Office 365/Sharepoint in the cloud implementation that will take a few years to roll out.

But recent moves by Microsoft suggest that the road to the future has some potholes. In particular, the slow (perhaps even dismal) sales of Microsoft Surface tablets is forcing the Redmond giant to rethink its strategy. Obviously, in a perfect world, companies of the near future would be running Office 365 (with Yammer, Sharepoint, and other supporting tools) on Windows Surface tablets. The future looks to be more inhospitable for Microsoft, however.

Apple continues as the undisputed market gorilla for tablet sales with no end in sight, and tablets are expected to overtake PCs in overall number in the next year or so, depending on whose numbers you believe. Microsoft’s efforts in this regard are not amounting to much, and Android is the dominant No. 2 in the market. (For the purpose of business use, we can forget Kindle, at least at present.) So Google’s recent agreement with HP — SMB IT in a Box — is an additional serious challenge to Microsoft’s efforts in the enterprise. HP is already selling Android tablets to its business customers and through its channel of resellers. Now it is adding an integrated solution for small and medium business, including Google Apps for Business, tablets, and a management software layer to control the deployment and integration of those elements with HP printers and other hardware. Another bite out of the huge head start that Microsoft has in the office software market.

Hardware is coming to be the tail that wags the dog in the office software space. People are now picking their tablet first and software last, because who really cares what software is being used to create a PowerPoint presentation or Word doc, now that Apple and Google can open them and edit them? The formats matter but the editors less so.

And of course, Apple’s announcement last week of a greatly improved iCloud and iWorks in the cloud is another nibble on the flank of Microsoft.

So the news this morning shows that Microsoft is now hedging its bets on Windows and Surface, stating that Office 365 and SkyDrive are now supported — in a limited fashion so far — on the iPhone. This app allows those subscribing to Office 365 and SkyDrive to access docs, make edits, and share documents. The limited nature of this is not the critical aspect but just that Microsoft felt compelled — presumably by customer demand — to support an iOS device at all.

The next obvious step is to accept the inevitable and disconnect Surface and the investment and market share inherent in Office and the strategic goal of getting Office users to transition to Office 365. It would be craziness to make this into a winner-take-all (or loser-lose-all) gamble. Instead, the sane strategy for the Office 365 team is to openly support all tablets and mobile devices, even if that supposedly undercuts Surface tablet sales. And since the enterprise — and even the desktop — is moving to the cloud, Office 365 management is making the right move, although we are waiting for the other shoe to drop. When will Microsoft release Office Mobile for iPad?