Network technology firm Juniper Networks has announced that it had hired an eight year Microsoft veteran- Brad Brooks.

Brad Brooks, who had managed the marketing of Windows Vista & Windows 7 at Microsoft, will be the vice president of Worldwide Enterprise Marketing & Solutions at Juniper.

It may be noted here that Mr. Brooks is the first executive who left the software giant to joint a rival firm. Kevin Johnson, the former chief of Platform & Services business at Microsoft, left the company in 2008 to become chief executive of Juniper.

Matt Miszewski, general manager of worldwide government at Microsoft, left the company to join Salesforce. com, while Johnny Chung Lee, who played a vital role in the development of the popular Kinect motion sensing add-on for Xbox 360 game console, left Microsoft to join Google.

A few days ago, Microsoft's CEO Steve Ballmer announced the plans to replace the chief of Microsoft's Servers & Tools Business division, Bob Muglia. Microsoft's chief financial officer Chris Liddell left the company at the end of last year.

Don Dodge, who is now working for Google, said, "Thousands of employees have been laid off or fired [from Microsoft] over the past two years."

Why Microsoft's top executives have been leaving the company is a billion dollar question.