I don't have any Sun Tzu memorized, but I bet that a good Windows Live search (See? It's already working!) would show that somewhere in the Art of War, it says that if you already have the land you want, stay there and let your enemies come to you. In some ways, this summarizes part of Microsoft's strategy. Microsoft is already installed on virtually every personal computer out there in some form or another. Even Apple's vaunted Leopard systems are for the most part loaded with Microsoft Office. So, it doesn't need to do anything to win over the PC computing space, except to not lose ground.
For that purpose, Microsoft has marched its sizable army of developers onto the battlefields that Google has contested. Google offers enormous amounts of storage for Gmail, so Microsoft does for Hotmail. Google has several other services that can be accessed by Google users, so does Microsoft. Google has an online office application suite, Microsoft has announced that it will too. Google has Picasa, Microsoft has Windows Live Photo Gallery. Google has Google Sites, Microsoft is readying a hosted version of Sharepoint.
The list goes on and on. Why, you ask, would Microsoft use its resources to develop free services like Google's when it could just keep making its regular installed applications better? Oh, Microsoft plans to make its installed applications better, but there is a method to the strategy as well. By having products similar in nature to Google's, Microsoft can prevent the defection of established business customers who already have untold dollars sunk into Microsoft products and support. As Apple learned the hard way, if everyone's company is dropping Microsoft on their desk, then the majority of people are going to be using Microsoft at home as well.
To see it better, picture this: A senior marketing executive with a lot of clout at a company is on the road with his laptop for 20 days. During that time, he stumbles across Google Docs and decides he likes it. Upon returning to the home office, he wants the company to start using and supporting Google Docs. Now, this is a big deal at most companies because they already have bought Microsoft Office for all the computers, they already have IT people trained to support those application, they have add-ons, scripts, deployment servers, upgrade cycles, and so on. So, when someone wants to add new stuff to the mix, there is going to be some push back. But, this guy pulls in giant sales and therefore usually gets his way. Is Microsoft doomed? Well, imagine the senior IT executive is having lunch with his friendly Microsoft rep and complaining about the prospect of having to support even more software without more staff. (Note: IT people love to have more stuff and would gladly add applications all day long if they got more budget and more people, but since new apps seldom come with either, they get grumpy about adding workload.)
Now, if the Microsoft rep has nothing to give the IT guy except a "don't do it speech," this fight is over. But, if the Microsoft rep can offer up say a comparable online version of the MS Office Suite already installed at the company, now we're getting somewhere. The exec returns to the home office to announce that after much research, he understands the benefits provided by being able to use online tools, but it will be too much work, money, and trouble to support Google Docs. Instead, the IT department will roll out a limited beta to the marketing group of the Microsoft version. Crisis averted. Oh, and by the way, the company will then probably block access to Google Docs in order to prevent unsupported use. As the marketing guys get used to Microsoft's online apps, do you think they'll actually go through the time and effort to also figure out and use Google's applications for their home use, or do you think they'll just keep using the good ol' MS version?