From the Microsoft-Watch article Google Pinches Another Microsoft Exec 

Google continues to hire away top Microsoft talent. But this time, Microsoft is fighting back. On Tuesday, Google announced plans to open a product research-and-development center in China, and said it was appointing former Microsoft vice president Kai-Fu Lee to head the operation. On Wednesday, Microsoft announced it was filing a lawsuit against Lee and Google, claiming breach of both employee confidentiality and non-compete agreement.
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Other mid-level Microsoft executives have joined Google over the past couple of years, as well. And Google opened a product-development office in Kirkland, Wash., late last year. Some industry watchers speculated that Google did so in order to attract more hires from Microsoft, which is headquartered in nearby Redmond, Wash.

It's the mid-level product and program managers whom Microsoft and other tech companies should guard most jealously, said Directions on Microsoft analyst Michael Cherry.

"While a lot of people make a big thing about the executives and senior vice presidents that leave, these people rarely ship software," Cherry said. "I think it is a bigger issue when the group program managers and program managers with ten plus years of experience silently leave. No one mourns their departure, but these are the people that take the grandiose architectures and wild-eyed visions and actually make them into products that people can use—and do so in a timely manner.

"The loss of these silent but hard working employees who keep the teams working together may have a bigger effect on the schedules of products like Yukon and Longhorn, and have a bigger long term impact on the company than any of the growing number of VPs and visionary architects," Cherry added.

From the Seattle PI article Ex-Microsoft exec sued over Google job

Microsoft also accused Google of "intentionally assisting Lee."

"Accepting such a position with a direct Microsoft competitor like Google violates the narrow noncompetition promise Lee made when he was hired as an executive," Microsoft said in its lawsuit. "Google is fully aware of Lee's promises to Microsoft, but has chosen to ignore them, and has encouraged Lee to violate them."
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Tom Burt, a lawyer for Microsoft, said Lee announced Monday that he was leaving for the Google job and had given no indication that he planned to honor an agreement not to work for a direct competitor for one year.

"To the contrary, they're saying, 'In your face,'" Burt told The Associated Press.

Google shot back with a statement saying: "We have reviewed Microsoft's claims and they are completely without merit. Google is focused on building the best place in the world for great innovators to work. We're thrilled to have Dr. Lee on board at Google. We will defend vigorously against these meritless claims."

Um, OK...