Microsoft is growing a huge campus in Google's backyard

Microsoft submitted plans to the city of Mountain View, California, for a major expansion of its office campus there. It wants to grow the size of its facility by 25% from over 515,000 square feet to over 644,009, reports the San Jose Mercury News.

It hopes to grow its employee base in Mountain View from about 2,000 today to as many as 3,000, according the Merc.

Microsoft's mothership campus is in the Seattle suburb of Redmond, Washington.

But as the tech talent wars heat up, Microsoft has increasingly pressed its way further into the Silicon Valley scene.

It opened this Mountain View office 15 years ago. The plan it submitted to the city would allow it "to build a state of the art facility to create an exceptional place to work," Microsoft exec Qi Lu told employees, the Merc reports.

Not only is it growing this office, but a few years ago it started holding its annual developer's conference, Microsoft Build, in San Francisco rather than Seattle.

The location of this campus is particularly interesting: Mountain View is Google's backyard. The Googleplex has slowly spread itself across much of that town. So Microsoft's outpost is a good way to watch Google, collaborate with Google and poach from Google.

We understand that Microsoft employees in the Bay Area are working on products such as Xbox, Outlook.com, Office for Mac, Skype and Yammer. Right now, Skype and Yammer have their own headquarters in Palo Alto and San Francisco respectively, so perhaps these employees will move to the expanded Mountain View campus.