WIRED:Both Apple and Google are wandering out of their core competencies into each other's territory, writes DANNY O'BRIEN

THIS WEEK felt like one of those moments in a science-fiction movie when the two main characters are popped into a mind-swapping machine. On Monday, Apple bought mobile advertising company Quattro, reportedly for $275 million (€192 million). On Tuesday, Google announced the Nexus One, its long-rumoured self-branded mobile phone. Apple got into advertising. Google started selling its own phone.

What is going on here? Both companies are wandering out of their core competencies into each other’s territory. Google’s cash cow is advertising; Apple’s is increasingly its mobile-phone division. Both risk annoying their own customers.

Google was long assumed not to be entering the mobile hardware market, for the good reason that its Android smartphone operating system depended on the goodwill of phone companies and other hardware manufacturers which would not take well to competition.

Apple’s foray into controlling advertising in the mobile market is bound to make its effective partners – developers creating apps on its iPhone platform – nervous.

On the other hand, Google and Apple are both old hands at trampling out of their comfort zone, straight into those of their soon-to-be ex-friends, and winning. It is long-forgotten now, but along with “don’t be evil”, one of Google’s original rules was to do one thing and do it well. That one thing was search. The rule was almost immediately broken when Google decided to do advertising and e-mail and then video, and then applications, and so on.

Apple Inc used to be Apple Computer, and kept out of the music, consumer electronics and phone markets – until it stormed all three.

What is significant about this week’s news is not the phone companies, the mobile advertising resellers and other slightly shell-shocked gangs. It is that Apple and Google are lining up against one another.

Compare these announcements to Microsoft’s damp-squib keynote by a greying Steve Ballmer at the Consumer Electronics Show in Las Vegas this week. Ballmer announced very little in the way of new products, services or software from Microsoft. He did mention HP’s new range of “slate” computers, but that was widely seen as a limp pre-attack on Apple’s expected announcement of a tablet-sized product later this month. What he praised was Bing, Microsoft’s frontal attack on Google’s search engine, which has been around far too long now, and failed to make a dent.

Bing and the slate computer do not feel like real forays against these big names. The old attack dog seems to be retreating increasingly into its safe domains of the Xbox and Windows updates, while lamely batting one paw outside its den.

Meanwhile, on the vacated yard, Apple and Google nervously circle one another, trying to work out exactly who is destined to take what in the new and emptier high-tech landscape.

In these kinds of battles, no one actually wins. Google doesn’t take all, and Apple doesn’t triumph. The battle is all about where the armistice is signed, and what innocent bystanders get hurt in the few real fights.

Right now we’re in the phoney war stage. No one has really noticed that Apple wants to do advertisements. Android and the Nexus One are not taking market from the iPhone; they are gouging out what remains of the iPhone’s competitors.

But sooner or later, there is going to be live fire between these two. There have already been some minor preparatory spats. Google has been the most upfront, by proposing a Google Voice application for the iPhone (which was rejected by Apple). The attack was successfully repulsed, and Google did not care enough to push harder.

Apple, too, has tried a few times to sidle into Google’s arena, and failed even on its own terms. It is significant that, while Apple’s designs do wonderfully in the “real” world, their internet offerings, such as .Mac or the original iPhone Web application model, have never really caught fire. People talk a lot about Apple on the internet, but you don’t see much Apple presence on the internet.

The real final battles between giants do not take place in the marketplace: they take place in the proxy world of the courts and regulatory space.

When Microsoft and Sun locked horns, it was in a lawsuit over Java. When IBM fell, it was because it was torn apart by the US courts.

So that is my prediction for the next decade. Apple or Google will find itself tripping over some legal or regulatory bind. While there will be no trace of the other in the lawsuit (neither company would be so gauche or so desperate to sue the other), the case will present an opportunity for the other, which it will take.

Perhaps Google will get hit by anti-monopolistic (or anti-American) regulation in the EU. Perhaps Apple will find its phone strategies being undermined by network neutrality and open hardware rules in the US.

Either way, come 2020, both these companies will still be around, and around each other’s necks, like boxers in the final rounds. And from somewhere will come a new contender who will exploit their obsession with each other and take whatever prize fight the next decade has to offer.