Microsoft and Apple have an interesting history that goes back to the early days of personal computing.
At times, Microsoft and Apple have fought like parents at a Little League game, squabbling over who copied whose tech.
On other occasions—usually behind the scenes—they’ve worked together on tech projects with mutual benefits.
Microsoft is still smarting from Apple’s devilishly effective “Get A Mac” campaign with John Hodgman and Justin Long.
But these days, there are signs that Microsoft and Apple are working closely to take on their mutual enemy, Google.
Here’s a look at the twists and turns of this love/hate relationship.
At Microsoft's Build developer conference this week, Microsoft used a Mac for an onstage demo of how Windows Azure cloud services being added to an iOS app.
Remember, Microsoft is company that pioneered the idea of using its own products, a concept known as 'dogfooding.' CEO Steve Ballmer is no big fan of Microsoft employees using Apple products, either.
So this was a big deal. And it shows how Microsoft is more open to working with other vendors, including Apple.
Box CEO Aaron Levie, who joined Microsoft Server and Tools chief Satya Nadella onstage, joked that Bill Gates was going to descend from the rafters to take away the Mac, as reported by ReadWrite's Owen Thomas.
Microsoft and Apple were talking about making Bing the default search engine on the iPhone back in 2010, according to Businessweek.
Earlier this month at its Worldwide Developers Conference, Apple made Microsoft Bing the default search engine for Siri in iOS 7.
Eddy Cue, Apple's senior vice president of Internet Software and Services made the announcement, the audience of developers gasped audibly in disbelief.
In a blog post, Derrick Connell, Microsoft's VP of Bing, said the deal was 'an exciting new chapter in Bing's collaboration with Apple.'
Apple did this because of its intensifying animosity towards Google, but still, this sort of partnership would have seemed extremely unlikely five years ago.
Microsoft and Apple both feel like Android is ripping them off. Microsoft thinks Android infringes on its Linux patents, while Apple thinks Android is a blatant copy of iOS.
So, when struggling Kodak put its imaging patents up for sale, Microsoft and Apple teamed up to bid on them.
Another group of companies bid on Kodak's patents, too. It included Google, Samsung, HTC and LG Electronics, The Wall Street Journal reported last June.
Eventually, Microsoft, Apple and Google united into one group and paid $525 million for Kodak's patents, with each company getting certain ones they wanted, Bloomberg reported in December.
Still, you'd have to think Microsoft and Apple would've preferred to keep the patents out of Google's hands.
With very little fanfare (OK, a complete absence of fanfare), Apple hired Francois Daumard, a 12-year Microsoft veteran who'd been working with the software giant's small and medium business customers.
Daumard was a very popular figure with Microsoft's business partners, who are experts at integrating its products.
At Apple, Daumard is still working with these Microsoft partners. That's because they can handle the back-end tech integration when a big enterprise buys thousands of iPhones and iPads and needs to tie them into its systems.
Apple needs Microsoft partners' expertise because it's own partners don't have much experience working with enterprises.
As Apple tries to capture more enterprise business, Daumard is one of the most visible figures leading the charge (and this being Apple, we use 'visible' in a relative sense).
In the span of a few months, Microsoft got really excited about bringing its apps to iPhone and iPads.
Microsoft released OneNote for the iPad, its first Office app custom built for Apple's tablet.
Microsoft also rolled out iPhone apps for SkyDrive, its cloud storage service, and Lync, its Internet phone and collaboration app.
In December 2011, Tom Rizzo, Senior Director of Office 365, Microsoft's suite of cloud productivity apps, told ZDnet's Mary Jo Foley that Microsoft is focusing more on iOS than Android.
'Android is more of a consumer device play. But iOS and iPad are mattering more in the enterprise,' Rizzo said in the interview.
Microsoft also announced it's working on an iPad version of Dynamics CRM (customer relationship management), which is software companies use to keep track of existing clients and find new ones.
rumours swirled in 2011 about Apple running part of its iCloud storage and file syncing service on Windows Azure, Microsoft's cloud.
In June, some Apple bloggers studied the traffic patterns of iCloud and deduced it was running on Azure as well as Amazon Web Services, Amazon's cloud.
Then in September, The Register quoted unnamed sources claiming that iCloud was indeed running on Azure and AWS.
Neither Apple nor Amazon commented on whether this was the case. Microsoft just said it doesn't name its Azure customers.
But the cloud makes strange bedfellows, and there are cases where rivals use each other's clouds because it makes business sense, so there may be some truth to this.
In an August 2011 blog post, David Drummond, Google's chief legal officer, sounded the alarm about what he described as a 'hostile, organised campaign against Android by Microsoft, Oracle, Apple and other companies, waged through bogus patents.'
As evidence, Drummond pointed to Apple and Microsoft's purchase of patents from Novell and Nortel, and claimed they bought them primarily to keep Google from getting them.
Eventually, Drummond noted, the U.S. Department of Justice stepped in and forced Microsoft and Apple to licence some of the patents to the open source community.
When Microsoft partnered with Apple in 1997, it inked a five-year deal to develop Office For Mac, its suite of productivity apps for Apple users.
Office For Mac ended up being a popular product, and Microsoft has a small business unit that still develops it.
In 2002, the contract expired, but Microsoft continued to make Office For Mac. Then in 2005, Microsoft re-upped for another five years and in 2006 pledged to make Office For Mac work with Macs running Intel chips.
Scott Erickson, who was director of marketing for Microsoft's Mac Business Unit at the time, told CNN Money in 2006 that the unit served an important function within Microsoft.
'It's the best of both worlds,' Erickson told CNN Money. 'We get to work with Microsoft's developers and have great partnerships with both the Mac and PC worlds.'
When Apple released its first version of iTunes for Windowsusers, Steve Jobs kicked off the launch event by noting that 'Hell froze over.'
'iTunes for Windows is probably the best Windows application ever written,' Jobs quipped at the launch event, as reported by Cnet.
Apple also played up the 'Hell froze over' theme in its marketing, handing out posters to attendees.
Jim Allchin, the former Microsoft exec best known as the head of development for Windows Vista, in 2003 saw two options for the future of Microsoft's Windows Media Player business.
The digital music players on the market then, from companies like Dell and Creative Technology, weren't even close to being as good as Apple's iPod, Allchin reckoned.
So Allchin proposed that Microsoft either make its own music player, or form some sort of partnership with Apple, according to court docs that surfaced in 2007 as part of an antitrust lawsuit against Microsoft, Computerworld's Eric Lai reported.
'I think I should talk with (Apple CEO Steve) Jobs. Right now, I think I should open up a dialog (sic) for support of the iPod. Unless something changes, the iPod will drive people away from (Windows Media Player),' Allchin is quoted as saying in the 2003 documents, as reported by Computerworld.
Microsoft ended up releasing the Zune, its iPod clone, a few years later. We'll probably never know if Allchin's idea for a partnership had legs, but the course of digital music history might have changed if it did.
The 1997 MacWorld conference in Boston will forever be seen as a turning point in Apple's history.
Steve Jobs announced a blockbuster partnership between Microsoft and Apple in which they'd licence each other's patents and work together on Java.
The big news, though, was that Microsoft invested $150 million in Apple stock, which at the time wasn't doing so hot.
Apple fans were stunned by the news. There was probably some cursing. And they booed heartily when Jobs announced that Apple was making Internet Explorer the default browser for Macs.
'What this means is that Microsoft is going to be part of the game with us as we restore this company back to health,' Jobs said.
But we all know what has happened since then.
Here's the video of Jobs announcing the Microsoft partnership:
OK, let's not get carried away: If Steve Ballmer caught a Microsoft employee using an iPhone, he'd probably smash it
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