Facebook's row over Vietnam photo shows how Mark Zuckerberg has become a media tycoon by stealth

Only a few days ago, Mark Zuckerberg told an audience of Italian students that he was the boss of a technology firm, not a media company.

Even at the time, it was clear that the Facebook boss was being disingenuous - either to his audience, or to himself. Because, as the Vietnam photo controversy has made glaringly clear, the 32-year-old is indeed a media tycoon. The most powerful one there has ever been.

Facebook is the place, more than any other, where the world spends its time. Once you take into account Instagram, which the company also owns, the site’s billions of users spend an average of 50 minutes a day posting pictures of their children, "liking" each other’s witty comments or swapping plans for the weekend.

It’s tempting to paint Zuckerberg, as a result of all this, as some kind of evil emperor. But the truth is, as his comments at the conference suggest, he doesn’t want to rule the world. For one thing, he doesn’t want the hassle.

The problem is that, by succeeding beyond his wildest dreams,Zuckerberg has become, as Espen Egil Hansen, the editor of Norwegian newspaper Aftenposten, says: “The world’s most powerful editor."

Facebook has effectively annexed, and privatised, the public square. That is a position of terrifying responsibility - perhaps for Mark Zuckerberg above all.