Ballmer: four million Windows 8 upgrades in four days

Greetings in beautiful, gray Redmond, WA. What better time to kick off year's Build event at the Microsoft campus than four days after the launch of Windows 8? CEO Steve Ballmer started the developer-centric event off with a nice little number: four million. According to the enthusiastic exec, that's the number of Windows 8 upgrades MS has seen in the four days since launch -- and there's certainly a lot of excitement around the operating system this tent full of developers.