Microsoft (NASDAQ:MSFT) hosted a media event at its Redmond headquarters last week, and CEO Satya Nadella gave some key insights to investors on where his priorities lie. At a high level, the CEO only cares about three things when it comes to customer usage and the source of Microsoft's revenue.

Unsurprisingly, they are Windows, Office 365, and Azure.

The big three
Of course, Windows and Office have long been Microsoft's two primary cash cows, followed closely by the company's server offerings. Compared to those three businesses, Azure is relatively young.

With the announcement of Windows 10, Microsoft is doing away with the distinction between Windows and Windows Phone. Windows 10 will operate on all form factors, including smartphones and tablets.

By specifically citing "Office 365" instead of just plain "Office," Nadella underscored just how important the shift to a cloud-based subscription model is for the company. When Office 365 was initially announced years ago, investors were skeptical about Microsoft's ability to successfully transition the business model of its most profitable business. More recently, those fears have subsided as the company continues to steadily grow Office 365 Home and Personal subscribers, which now top 7 million.

Source: SEC filings; calendar quarters shown.

Nadella has also shown a penchant for broadening Microsoft's mobile strategy, most recently by releasing new apps that include additional free features to appeal to consumers.

Azure is the new kid on the block, crossing the $1 billion revenue threshold for the first time in 2013. Microsoft does not break out Azure revenue specifically, but did mention that it soared 121% last quarter as the customer base grows and customers commit to higher levels of spending alongside higher use.

Cloud computing platforms like Azure appeal directly to smaller companies that lack the scale to spend heavily on infrastructure. Right now, 40% of Azure revenue comes from start-ups and independent software vendors, according to Nadella. Microsoft is being aggressive with the commoditized aspects of cloud computing in order to win over the "differentiated higher-margin workloads" from the likes of Amazon Web Services or Google Compute.

What didn't make the cut?
As interesting as what Nadella is focusing heavily on is what he's not. Xbox has become one of Microsoft's most prominent businesses, though more in consumer mindshare than financial results. Despite some recent speculation to the contrary, Microsoft confirmed over the summer that it remains committed to the video game console.

There are some development synergies around graphics and speech recognition, among others, that Microsoft can take from Xbox back to its core businesses. At the same time, Xbox can be used as a moat-building tool to a certain extent.

Likewise, Bing isn't included on the list. But Bing is also an important aspect of how Microsoft hopes to monetize Windows in the future for low-cost devices. Importantly, Windows with Bing is starting to gain early traction with OEMs, grabbing over 50 new hardware partners since being announced earlier this year.

Nadella said everything else that Microsoft does is an extension of these three core services (he went as far as to characterize Windows 10 as a service). That's the right approach in a cloud-first, mobile-first world.