Sony used its E3 press conference to announce a slate of quirky, weird, and almost-forgotten titles, but among the likes of The Last Guardian and the upcoming Final Fantasy VII remake was the company's most nakedly commercial announcement: extra downloadable content for the next Call of Duty game would be coming to PlayStation first.

In an age where true platform-exclusive games are few and far between, Sony and Microsoft have secured DLC deals with other publishers to differentiate between the PlayStation and Xbox versions of new games. By stumping up undisclosed sums of cash, the platform holders have been able to get new exclusive maps, special weapons, and early beta access, tempting passionate and impatient fans to their side with minor additions to the biggest games. And none have traditionally come bigger than Call of Duty. The shooter series has generated $10 billion for publisher Activision over the past decade, growing from fairly humble beginnings as a World War II FPS to become a sci-fi staple pegged to a yearly release schedule, reliably selling tens of millions of copies with each iteration.

Sony has a similar deal in place with Activision for the PS4 version of Destiny, but the announcement of the new Call of Duty deal marks the first time the Japanese company has secured DLC exclusivity for the series. The new deal replaces a long-standing agreement between Microsoft and Activision that previously ensured that owners of Xbox consoles saw new map packs and add-ons a month before PlayStation gamers, a feather in the company's cap that it showed off at every E3. The question is now whether Sony stole the rights from under Microsoft's nose, or whether Microsoft was simply happy to let the deal lapse.

Perhaps Microsoft realized CoD was finding more of a home on Sony's console. Reports last year indicated that of the 11.44 million units 2014's Call of Duty: Advanced Warfare sold in its first month at retail, 4.01 million went to PS4 players, and only 2.61 million to Xbox One owners. But those figures don't necessarily mean Xbox players are particularly sick of CoD — in November last year, Sony's console was cheaper than its rival's and riding on the back of a successful PR campaign that put it in the ascendancy. It may be, instead, that Microsoft foresees a time when Call of Duty's popularity is waning. Indeed, we may be on that path already. Sales seem to be slowing for the series, with Advanced Warfare reportedly underselling predecessor Ghosts by some 27 percent in the US.

But even if Call of Duty doesn't maintain its staggering market performance forever, by securing CoD DLC exclusivity, Sony has pulled off a fairly hefty theft from its biggest rival. The PlayStation 4 is now the de facto home for two of the world's biggest games, and dedicated players of both Call of Duty and Destiny would sensibly choose the console to get their hands on weapons, items, and maps first. As third-party publishers release on all platforms to maximize their profits and triple-A first-party games take more time and more money to produce, we can expect to see similar exclusivity deals changing hands in the future, with the two core console platform holders clawing to use major games to make minor distinctions between their black boxes.