David Weinberger has a new book out entitled Too Big to Know in which he argues that one of the implications of a comprehensively networked society is that the nature of knowledge itself is changing. "As knowledge becomes networked," he writes, "the smartest person in the room isn't the person standing at the front lecturing us, and isn't the collective wisdom of those in the room. The smartest person in the room is the room itself: the network that joins the people and ideas in the room, and connects to those outside of it... Knowledge is becoming inextricable from – literally unthinkable without – the network that enables it."

A few days ago he gave a stimulating talk at the Berkman Centre in Harvard in which he set out his ideas. I was struck by one of his slides, which stated Weinberger's equivalent of Newton's first law: "For every fact on the internet, there is an equal and opposite fact." To those of us who were reared on Daniel Patrick Moynihan's famous dictum that "everyone is entitled to his own opinions, but not to his own facts" this came as a bit of a shock; and I distinctly heard a faint whirring sound as CP Scott rotated in his grave. But that seems to have been Weinberger's intention: to shock his audience into realising that the rules of the ontological game may be changing.

The motto of the News of the World used to be that "all human life is here". It was never true of that lamentable organ, but it does seem to be true of the internet. Every imaginable philosophy and opinion is being expressed out there, somewhere. In principle this is wonderful; but in practice it is unmanageable. So we have evolved a way of coping with the overload: filtering out what we don't want to hear and clustering in "digital echo-chambers" in which we only pay attention to those with whom we agree.

Which is why we need contrarians such as Evgeny Morozov. He first came to prominence with a provocatively titled book, The Net Delusion: The Dark Side of Internet Freedom, in which he ridiculed digital utopianism and trashed the idea that the internet was inevitably a liberating technology. "To assume," he wrote, "that a government would be choosing between reading their citizens' emails or feeding them with cheap entertainment is to lose sight of the possibility that a smart regime may be doing both."

The point of contrarians is that they come at things from left field, challenging received wisdom or puncturing bubbles just as they are beginning to overinflate.

Which brings us to the question of the Facebook IPO. Morozov wrote a fascinating essay for the New York Times that started out in belle époque Paris but wound up nailing the Facebook ideology. In the early days of the web, Morozov argued, before it was colonised by commerce, the internet was like a cabinet of curiosities and surfers were like the flâneurs of 19th-century Paris. "The flâneur," he writes, "would leisurely stroll through its streets and especially its arcades – those stylish, lively and bustling rows of shops covered by glass roofs – to cultivate what Honoré de Balzac called 'the gastronomy of the eye'. The flâneur wandered in the shopping arcades, but he did not give in to the temptations of consumerism; the arcade was primarily a pathway to a rich sensory experience – and only then a temple of consumption. His goal was to observe, to bathe in the crowd, taking in its noises, its chaos, its heterogeneity, its cosmopolitanism."

Two developments, Morozov maintains, did away with the flâneur: the rise of department stores, which destroyed the arcades; and Baron Haussmann, who remodelled the urban maze of medieval Paris into a tidy metropolis of wide boulevards that facilitated troop movements and cannon fire.

In Morozov's view, something similar has happened to the internet. It's no longer a place for strolling – it's a place for getting things done. "Hardly anyone 'surfs' the web any more." Mobile apps, which bypass most of the internet, make cyberflânerie less likely. And much of today's online activity revolves around shopping. "Strolling through Groupon isn't as much fun as strolling through an arcade, online or off."

So Amazon is the equivalent of La Samaritaine – a place you go to buy stuff. And Facebook? Ah well, says Morozov, Zuckerberg wants to wipe out the individualism that was at the heart of flânerie. He wants everything to be "social". "Do you want to go to the movies by yourself," he asked recently, "or do you want to go to the movies with your friends?" His answer: "You want to go with your friends." My answer: I'll go by myself, thank you. But then I'm so 19th century.