If nothing else, Microsoft's keeping business consultants busy

It's the biggest Microsoft reorganization in five years. CEO Steve Ballmer promises that the changes will lead to better execution. (You can read his full letter that was released Thursday here.)

Making good on that promise will involve the elimination of the current five Microsoft business units along with the merger of all three Microsoft operating systems into a single division. Also, marketing and business strategy decisions will get centralized in cross-company groups.

But will any of this lead to the more agile and responsive tech company that Ballmer wants? Maybe. But if past is prologue, maybe there's still more corporate calibration to come. Spoiler alert: In the last decade, Microsoft reorgs have almost become an annual event.

• 2012: Early in the year, Microsoft reportedly cuts a couple of hundred jobs in a marketing restructuring. Microsoft says the steps will boost the "effectiveness and efficiency of our marketing" and better "clarify roles."
• Ballmer announces a big shakeup in November 2012 at the top with Windows President Steven Sinofsky leaving the company. That one came out of left field as Sinofsky's name often came up in discussions about who might follow Ballmer as CEO. But he is also described as being a polarizing figure who had his share of disagreements with his boss. Sinofsky's duties get farmed out to a couple of up-and-comers at Microsoft. Julie Larson-Green receives Windows engineering, including responsibility for all product development for Windows and Windows Live. Tami Reller takes over the business and marketing strategy for Windows, including Surface and partner devices.
• 2011: Microsoft creates a new division focused on advertising and online, putting it all under Frank Holland.
• 2010: Two high-profile execs, Robbie Bach and Chief Technology Officer J. Allard are now no longer in the picture. After two decades at Microsoft, Bach is out while Allard becomes an adviser to Ballmer on unspecified special projects. All this takes place as Microsoft takes heat for not focusing sufficiently on mobile because of the primacy put on its Windows and Office franchises.
• 2009: Microsoft splits up the Zune hardware and software teams amid its first-ever company-wide layoffs. Enrique Rodriguez, the VP running Microsoft's Mediaroom and Media Center TV businesses tells CNET that the company's "just being very pragmatic and even more so in a world in which not even Microsoft can afford to over-invest. Zune gets added to his existing portfolio. But not for long as Microsoft kills off the device a couple of years later.
• 2008: Ballmer splits Microsoft's Platforms & Services Division into three units -- Windows, Online Services, and Server and Tools. Kevin Johnson, president of the division in charge of platforms and services and once considered a possible heir apparent, resigns after 16 years at Microsoft. In announcing the overhaul, Ballmer writes: "Our Windows business is firing on all cylinders. We see tremendous opportunity in search and advertising, and we have a clear strategy for investing in success today and growth in the future."
• 2007: Microsoft reorganizes its Windows marketing group with Kevin Johnson gaining attention as a power to be reckoned with. Up until that time, he had run the group with Jim Allchin.
  
  • 2006: A couple of days after announcing the delay of Windows Vista, Microsoft breaks its Windows division into eight groups Steven Sinofsky gets put in charge of the new Windows and Windows Live group. He is also given the task of quarterbacking planning for Microsoft's post-Vista future. Sinofsky, who gained a reputation as a polarizing figurewithin Microsoft, would go onto clean up the Vista mess and revive the Windows franchise with solid updates in the form of Windows 7 and Windows 8.
  • 2005: Microsoft again refashions the organization, this time around three big divisions all reporting to Ballmer. Jim Allchin, the longtime head of Windows development, announces his pending retirement. The new structure leaves Jeff Raikes to head up the company's business division, Kevin Johnson in charge of platforms and services division, and Robbie Bach running games and mobile device development. In his statement to employees explaining the reorganization, Ballmer writes that the changes will lead to a more streamlined decision-making process and better product development. "We see a new era of opportunity to provide greater value to our customers by weaving both software and services into forms that suit their needs. By bringing together the software experience and the service experience, we will better address the changing needs of our customers' digital lifestyles and the new world of work."
  • 2002: Rick Belluzzo, a former rising star at Hewlett-Packard, arrived at Microsoft in 1999. Three years later, a a reorganization cost him his job as president and chief operating officer. At the time, Microsoft said the reorganization would empower the heads of its business units with more autonomy. As a result of the shakeup, the units would now report directly to Ballmer. "We realized we needed to give our core leaders deeper control and accountability in the way they run their businesses," Ballmer told employees in a company-wide e-mail.
  • 2001: Not technically a corporate shuffle but more of a reorganization with the aim being a sharpening of the company's sales focus. More here.