In 2011 alone, 380 billion photographs were taken.

According to the New York Times, this accounted for fully 11 per cent of all the images ever captured in the medium. By the following year, when Eastman Kodak filed for bankruptcy, there were 500 billion pictures on Facebook.

The numbers are a marvel, of course. They attend ever announcement of the brave new world that is transforming us - our jobs, our social relations, our culture, our politics - with each passing day. They can seem, sometimes, like a statistical portrait of a species evolving before its selfie-obsessed eyes. We admire ourselves, we advertise ourselves, we talk to ourselves - and we assure ourselves this is progress.

Only God and the search engines can guess how many pictures will be taken this year, most of them on smartphones or tablets. We can be fairly sure, however, that the greatest number of images will be forgotten the instant they are snapped. Our collective self-portrait will form no part of a shared history, or even a shared memory. Billions of human moments are being forgotten within seconds of the act of recording. The act, supremely narcissistic, is the only point.

An internet evangelist might call that supposition. What we know for sure is that the old Kodak company, a dinosaur from another era, once employed 147,000 people. Now it is reduced to a handful of thousands struggling to find a niche. When the slow-moving, mismanaged firm crashed, most of the 147,000 and generations of loyal predecessors lost their pensions. "Creative destruction!" evangelists would cry. Andrew Keen wants to know what's so great about that.

As a disabused evangelist himself, he has no desire to claim that all the golden apples of the internet are poisoned. When he matches promises against reality, however, Keen concludes that questions - a lot of questions - are in order. Does the networked world provide jobs, general prosperity, and equality of digital opportunity? Quite the reverse. Does access to stupendous amounts of information make us better-informed, or even - for here nerds grow mystical - better people? Take a look at Twitter and despair.

The relentless assault contained in The Internet Is Not The Answer describes a handful of Silicon Valley robber barons who talk a lot about freedom while exploiting billions of willing suckers. The juvenile entrepreneurs have made themselves grotesquely rich with a seductive lie: it's all free. What's more, anything on the internet should, must, indeed "needs" - perhaps the most vacuous claim ever made - to be free.

How does that work? Facebook doesn't bill you; Google doesn't require a card number; Instagram will vault your precious photographed moments into the ether at no charge. Apps are handed out like candy to infants. You are implored, daily, to take up unmissable networking offers. Yet somehow the youngsters behind these gee-whiz enterprises - not to mention their somewhat older venture-capitalist backers - wind up with extraordinary fortunes. And all from free stuff?

For traditional industries, there has been carnage. Keen quotes the singer Paul Simon, a figure who is a long way short of his last dollar thanks to old ways of selling music. "I'm personally against Web 2.0," says the writer of "Keep the Customer Satisfied", "in the same way as I'm personally against my own death." Simon speaks for an industry brought low by theft - bootlegging, piracy - founded on the lie that everyone is entitled to everything created at no charge whatever.

That's a problem. Spotify, the music-on-demand service, makes payments so pitiful it leaves young musicians yearning for the days of rapacious record deals. Amazon's remarkable book bargains, despatched from hell-hole tax-avoidance sheds by electronically-tagged serfs, have eradicated local shops, killed the jobs the shops once supported, turned publishers into fragile dependants, and rendered writing a client hobby. As Keen reports, Jeff Bezos and his Amazon venture are identifiable destroyers - not creators - of employment.

Like good robber barons, Bezos and his kind follow capitalism's logic. What was the chief impediment to old-hat capitalism? People. People and their minimum wages, their health needs, their trade unions, their foibles and their families, and - the bottom line - their cost. Keen is especially good on the Silicon Valley visionaries and robotics, the current obsession. In any proper cost-benefit analysis, after all, the human factor is just a challenge to be overcome.

You can chuckle over these clever folk and their plans for driverless vehicles. If you indulge them, you can regard a future in which your Amazon order comes from a wholly automated factory straight to your door by pilotless drone as pretty - that entirely Californian word - cool. So: how many packers, truck drivers, postal workers, cab companies, bus drivers and the rest could be caused to disappear? Keen is clear: the clever folk aren't kidding and it is already happening.

While they count their billions, the entrepreneurs paint themselves into ever-smaller corners. Keen does an able job of describing, for one example, the decline and fall of news media in an age that demands free information. You want facts? A journalist raising a family might have a quaint need for payment before he or she puts in the hours. But you despise the "mainstream media"? Stop obsessing about it on Twitter. Then recognise the economic cost - for Silicon Valley won't - of an informed electorate.

Keen, educated as a historian, is not in the business of assailing technology. The decline in average earnings across the western world - down by 28 per cent in real terms for American males in the last 40 years - can't be blamed entirely on the overlords of the networked age. But they exploit, advance and, indeed, celebrate that state of affairs. Anyone concerned about inequality should wonder about free stuff. It means, in essence, that a lot of people, factory hands or photographers, are not being paid.

In April 2012, when Instagram was sold to Facebook for a billion dollars, the snap-happy start-up "still only had 13 full-time employees working out of a small office in San Francisco". Even by capitalism's reckoning, that billion was not "productive". How does a world of falling wages prosper if the net barons decree that all must be free? What they mean is that you work for them with every Google search and every tweet. For no payment, you are supplying data in quantities that would cause GCHQ to reel.

It's sold, all of it, to advertising, in ever-increasing quantities, with ever-increasing degrees of sophistication. The shiny internet revolution depends ultimately on flogging statistics of habits, beliefs, appetites and desires to advertisers by Facebook, Google, Twitter and the rest. Our value is in our data. Aptly, Keen describes the big names of the digital world as "data factories". A parasite technology: that's where billions are made.

There's a paradox, of course. If we become impoverished or unemployed, if we are rendered insecure and deprived of hope as inequality is made permanent, to whom will advertisers advertise? If you turn people into commodities, it's wise to place a value on the goods. If not, remember to take a snap of yourself when understanding dawns.