The tech world just witnessed a robbery. The heist was so brazen you kind of had to admire it, even if it was pulled off with all the grace of a petrol station stickup.

Facebook barged into Snapchat's happy California mansion, took a solid inventory of the goods, then lifted the crown jewels. First a version of Stories, the fun slideshow format that Snapchat created, appeared last year on Instagram, owned by Facebook. Then Snapchat's features made their way to WhatsApp and Messenger, Facebook's chat apps. Recently they got Facebook's main app and the heist was complete.

On April 18, the leader of the Facebook crew, Mark Zuckerberg, put on a conference to show off his loot. But he went further: He unveiled a vision of augmented reality in which digital objects and effects are overlaid on images of the real world which could undercut Snapchat's mission to become the camera company for the next generation.

His speech had a lot of corny jokes, but that was just Zuckerberg's way of hiding the shiv. In reality it was a performance that made plain Zuckerberg's ruthlessness as a businessman. It also shows that he understands Facebook's most important assets. Zuckerberg realised early on that the most important thing in his business was not necessarily creating the best new features. It does not matter who invents digital moustaches. What matters is owning the biggest and most engaged network. And because he has the network, he always wins.

For years now, the world has been doubting Zuckerberg. Facebook, they said, would never beat Myspace. Then Facebook was going to get a run for its money from every other social network - Twitter, Pinterest and more. Hey, could it survive Google's onslaught? Could it survive its own initial public offering? How would Facebook adjust to mobile? What about live video? And then there was Snapchat. By turning the smartphone camera into a communications platform, Snapchat created a novel and compelling social experience. Teenagers couldn't get enough of it. And teenagers are the future. If Facebook lost teenagers, game over.

Hahaha. In the big picture none of these things really made a dent in Zuckerberg's expanding kingdom.

Five years ago, after more or less cementing Facebook's status as the world's largest social network, he began to buy up and build future networks. He bought Instagram, which now has 600 million users. Then he bought WhatsApp, which has more than 1 billion users. Then he turned Facebook's baked-in chat feature into its own chat app, Messenger, and now that, too, has 1 billion users.

He offered Evan Spiegel, Snapchat's co-founder, $US3 billion ($4 billion) to buy that app. Spiegel refused but perhaps he should have taken a closer look at the networks Zuckerberg was assembling.

Do you know what happens when you control four of the biggest social networks in the world? You get to stop worrying about competitors beating you on features.

Zuckerberg had done it before: Every time some other social company came up with social features that people seemed to enjoy - Twitter with the follower mechanism, Foursquare with checking in to stuff, Vine with short videos, Periscope and Meerkat with live video - Facebook or one of its subsidiaries (or all of them) could just copy and co-opt.

Zuckerberg did not win all of this stuff; sometimes the features turned out to be less important than initially thought, but that did not matter. At the very least he would neutralise his enemy's growth, cutting it off before it became an existential threat to Facebook.

And that is what we have just seen with Snapchat. There is a debate in the tech press about whether Facebook's shrewd copying has killed Snap, Snapchat's parent company, or simply wounded it. After all, Instagram recently said that 200 million people a day were using its Stories feature, which is more users than all of Snapchat (160 million at last count).

When you directly copy someone, that's not innovation

Miranda Kerr

But that is not the right question to ask. Snapchat could well survive, even thrive. The world is big; it can coexist with Facebook.

What is important is that Facebook has forced this coexistence. Facebook's billions of users will now be introduced to Snapchat's best features on Facebook's own platform, eliminating, for a lot of them, any reason to switch. There is essentially no chance now that Snapchat will eclipse Facebook anytime soon, if ever. In other words, Zuckerberg has done it again; he has neutralised yet another rival.

But there is another aspect to the power of large networks: They make other people's features better.

During his speech, Zuckerberg previewed a slate of new tools to turn Facebook's built-in camera into a platform that outside developers can add to and improve. Snapchat has made a hit out of augmented reality - the tech term for adding cartoony digital effects on your pictures and videos, like rainbow vomit pouring out of your mouth or dog ears on your head. But now Facebook, with its deep investments in artificial intelligence (which it uses to power all of its other apps) and its broad connections with developers (who want to get to its billions of users), will be in a far better position to advance those ideas.

"Even if we were slow to add cameras to all our apps, I'm confident that we're going to be the ones who push this technology forward," Zuckerberg said.

Let us end with a note on the ethics of all this. Some of you may find it upsetting that a big company can just lift an innovation from a small company and run with it. If it's not illegal, isn't it at least something we should discourage?

Miranda Kerr, who is Spiegel's fiancee, recently told The Times of London that she could not stand Facebook's behaviour.

"Can they not innovate? Do they have to steal all of my partner's ideas?" she asked. "When you directly copy someone, that's not innovation."

To which I say: Whatever. There are lots of different kinds of innovation in the tech industry. Coming up with something first is not the only kind.

There is a rich history in this industry of taking someone else's idea and adding your own spin on it to improve tech for everyone. Apple's Steve Jobs and the team behind the original Mac were inspired by a bunch of ideas floating around tech research circles, including at Xerox PARC. Then Microsoft's chief executive, Bill Gates, saw the Mac's success and by creating a new business model for the PC industry he ushered in an even bigger deal: graphical computers that could get cheap enough for most people to own.

Or look at the smartphone. Apple created the iPhone, but if the tech industry had stopped there, smartphones wouldn't have swept the world very quickly. Instead, Google more or less copied Apple's software ideas in early versions of Android, and Samsung essentially copied Apple's hardware. Economics kicked in, smartphones got really cheap, and they flooded the globe. And everyone did better: In time, Samsung hit on its own big idea huge phones that Apple copied, and Apple then made a bundle.

So let us not get too hung up on copying. All is fair in love and rainbow vomit.

The New York Times