Why is Microsoft buying LinkedIn?

Microsoft just surprised the world with its LinkedIn acquisition. Valued at $26.2 billion, it's a huge price to pay for a social network, and it tops the charts as Microsoft's biggest-ever acquisition. As Microsoft CEO Satya Nadella's first major acquisition, the success or failure of LinkedIn will define him as the leader of Microsoft's increasingly service-driven future. While many are surprised at the cash figure, the question on everyone's lips is, why does Microsoft want LinkedIn?

Nadella's internal memo does a good job of providing a basic outline to partially answer that question, and more. Nadella points out that LinkedIn is "how people find jobs, build skills, sell, market and get work done." It's a key tool in the professional work space, with 433 million members and more than 2 million paid subscribers. Microsoft itself has more than 1.2 billion Office users, but it has no social graph and has to rely on Facebook, LinkedIn, and others to provide that key connection. LinkedIn provides Microsoft with immediate access to more than 433 million members and a solid social graph that, thanks to its professional nature, is matched closely with the software and services Microsoft provides. In the same way that most kids play Minecraft, it's reasonable to assume most adults in the US use LinkedIn for finding jobs, connecting with colleagues, or just general work-related networking.