Microsoft has recently launched an all-out advertising assault against Google, attacking everything from the company's privacy policies to what Microsoft considers the inadequacy of Google Apps. Meanwhile, it's been mum about Apple, and some unconfirmed rumors say it might even be developing an Office app for the iPad. Here are three reasons Microsoft fears Google more than it does Apple.

The fight for the enterprise

With Google Apps, Google has taken dead aim at the core of Microsoft's business --- the enterprise. Windows is no longer Microsoft's cash cow; Microsoft's business offerings have eclipsed it. The two largest revenue generators for Microsoft are now the Business Division and the Server & Tools Division. Google Apps threatens both those divisions. Apple, meanwhile, may make short-term gains in the enterprise, but, in the long run, it cares more about consumers than the enterprise, so it doesn't threaten Microsoft.

That's why Microsoft recently released a scathing anti-Google Apps video on YouTube, titled "Googlighting," which features a slick, sleazy salesman pitching Google Apps. Microsoft's Tom Rizzo says on his blog: "Many businesses find that Googlighting also means taking shortcuts, making assumptions about how people should work, and generally failing to build and deploy solutions which meet a wide range of business needs."

The fight for Office suites

Office represents another cash cow for Microsoft (it's part of the Business Division), in the enterprise as well as for consumers. And Google Docs directly targets Office, both as a free consumer service as well as part of Google Apps.

If Office loses ground to Google Docs, not only will it be hurt with consumers, but if it becomes more widely accepted, enterprises may consider it, and ultimately use Google Apps as well.

Unverified rumors surfaced this week that Microsoft has been developing an Office app for the iPad, and although Microsoft has denied them, it has done so in a way that leaves open the possibility that such an app is in the works. An Office app on the iPad would certainly help fend off Google Docs.

The fight for search

Google continues to dominate Internet search, but Microsoft recognizes that it needs to have a serious search presence if it is going to grow and thrive on the Internet as well as in mobile. So Microsoft continues to spend serious money to build and promote Bing. Google isn't giving an inch, for example outbidding Microsoft to keep Google search as the default search engine for Firefox.

To try and scare people away from Google search, Microsoft has targeted Google on privacy issues, via advertising campaigns as well as blogs and charges to the press. When the Wall Street Journal charged Google with avoiding privacy protections in Apple's Safari browser, Ryan Gavin, Microsoft's head of marketing for Internet Explorer charged, "This type of tracking by Google is not new. The novelty here is that Google apparently circumvented the privacy protections built into Apple's Safari browser in a deliberate, and ultimately, successful fashion."

Clearly, criticizing Google on privacy is one of primary ways Microsoft hopes to gain market share.

This story, "Why Microsoft is More Afraid of Google Than Apple" was originally published by Computerworld .