Facebook CEO Mark Zuckerberg speaks on stage during a town hall with Indian Prime Minister Narendra Modi at Facebook's headquarters in Menlo Park, California September 27, 2015. REUTERS/Stephen Lam Facebook has made good on a promise it made to Microsoft last year with the delivery of a trio of new apps for Windows 10: Facebook, Facebook Messenger, and Instagram.

It's a big step forward for Windows 10 — these apps, available from the Windows Store, will work on any Windows 10 device, including PCs, tablets, and even Microsoft's struggling Windows 10 Mobile phones.

More popular apps like Facebook on Windows 10 means more people willing to give Windows 10 a shot. And Facebook is committed to getting its apps and services in front of as many people as possible, everywhere.

It's also a sign that despite their sometimes-rocky history together, Facebook and Microsoft are getting extremely cozy as their visions for the future start to align. In fact, Microsoft is treating Facebook more like an equal.

History lesson

Microsoft and Facebook go way back to the early days of the social network. In 2007, Microsoft invested $240 million in what was then a promising young startup, for a 1.6% stake. Over the years, the two announced some joint technology deals, like using Microsoft Bing for searching that fell by the wayside as Facebook rapidly matured and started building its own technology in-house.

Fast forward to the present, and Microsoft CEO Satya Nadella has demonstrated time and again a willingness to work with competitors: Nadella's Microsoft has refocused on providing useful, helpful services to developers and consumers alike, no matter what device or operating system they're using.

That's good, because Mark Zuckerberg has outlined an extremely ambitious 10-year plan for Facebook that combines augmented and virtual reality with artificial intelligence. Which is to say, Facebook has a lot of talent and expertise, but it can't make this future happen all by itself.

Microsoft CEO Satya Nadella REUTERS/Baz Ratner

There are two factors that make the newer, friendlier Microsoft an ideal partner for Facebook: First off, Microsoft doesn't really have much of a social networking play, and it's divested itself of most of its advertising business, meaning that it's rarely going head-to-head with Facebook.

Second, and more importantly, Microsoft has invested much of its vast fortune and resources into solving many of the same problems that Facebook is tackling. Just a few weeks ago, Nadella announced Microsoft's strong belief in "conversations as a platform," while Facebook is selling "the Messenger Platform."

In both cases, they're talking about chatbots, the current fad in Silicon Valley where you can text with a machine like it's a human.

It's not hard to imagine developers using Microsoft's tech to build their chatbots on the Microsoft Azure cloud, and then plugging them into the Facebook Messenger platform. The net effect there is more chatbots on Messenger, which is good for Facebook, using the Azure cloud, which is good for Microsoft.

They even signed a deal to bring Facebook's popular React Native framework to Windows apps, which brings more developers to both companies.

Virtual insanity

And at Facebook's F8 conference earlier in April, Zuckerberg announced that the company's Oculus VR subsidiary is working to eventually create a pair of glasses, just like your normal average horn-rims, that provide both virtual reality (totally cocooning you in the virtual world) and augmented reality (which overlay computer images over the real world).

Now, Facebook already has the Oculus Rift virtual reality headset, but there's no indication that it's actively working on augmented reality. But Microsoft, Facebook's apparent new bestie, has its HoloLens, which is currently the only high-end augmented reality headset you can buy,though it's a hefty $3,000.

You need a Windows PC to run the Oculus Rift. Business Insider

Indeed, Microsoft's gaming division and Facebook's Oculus have their own little partnership going on, to support Xbox One games in virtual reality with the Oculus Rift.

Besides, you need a Windows computer to use the Oculus Rift headset in the first place — which is good for Microsoft, too, because it means they get to ride the virtual reality wave with Windows, without their having to go out and build their own device. Going forward, you can probably expect more handshake deals along these lines between the two.

All of which is to say that Microsoft and Facebook seem to be realizing that they can do more for each other by working together than by working separately. And while we're past the days where Microsoft treated Facebook like an investment, they seem to be marching together into the future as true partners.