According to Microsoft's Satya Nadella, LinkedIn is a perfect fit. You need a "connected professional world" to get things done, he says, whether it's getting help with a spreadsheet or fleshing out details in a customer relations tool like Microsoft's Dynamics. And while Microsoft is purposefully keeping itself at arm's length, Nadella sees the potential for revenue through subscriptions and (like it or not) targeted ads.

Suffice it to say that this is a huge move for Microsoft. It's entering the social networking world in a big way -- while LinkedIn isn't direct competition for Facebook or Twitter, its 433 million members are nothing to sneeze at. The acquisition is also proof positive that Microsoft under Nadella is reducing its dependence on Windows and putting more of an emphasis on cloud services. This is as much about acknowledging a changing computing landscape, where Windows doesn't necessarily dominate, as it is a bid to become a crucial service provider.