Welcome to Googletown, where, as you sip your skinny decaf, a cup-embedded chip instantaneously analyses your salivary DNA, allowing café staff to greet you personally as their screens retrieve your online profile. Stroll down the street, and an eye-scanning digital billboard reminds you to buy a birthday present for your mother, helpfully suggesting the perfume brand she e-mailed a friend about last week. Then, just as your internet-enabled Nikes are offering to guide you to the nearest discount perfumier, your phone buzzes with the message that will change your life. As your marriage seems to be going nowhere, it suggests, you might like to know that a woman shopping two streets away offers you an extraordinary 96 per cent compatibility rating. Simply click “Yes” and leave it to Google’s algorithms to play Cupid.

It is not a far-fetched vision for the company committed to “organising all the world’s information”. This week, Google’s chief executive, Eric Schmidt, declared that his business was only just beginning to accumulate personal data about its users. “We cannot even answer the most basic questions because we don’t know enough about you,” he said. “The goal is to enable Google users to be able to ask the question such as, ‘What shall I do tomorrow?’ and ‘What job shall I take?’ ” In other words, a service that you began using simply to find websites intends to monitor your deepest motivations. At what stage did the “don’t be evil” start-up evolve into the information society’s most determined Big Brother?

Don’t underestimate how much information Google already holds on you. Sign up for its free services, and it monitors your search history, news interests, map directions sought, photographs viewed, investments made and products shopped for. It stores each e-mail you send and receive “for ever”, indexes the files stored on your home PC, collects your instant-message chats, and knows what is on your calendar and to-do lists – all while linking your online trail to a personally identifiable Internet Protocol address (and whatever credit-card details you provided for its shopping service, and home postcode you gave its mapping service). If you want a flavour of the databank it has accumulated about you, simply log into its new “iGoogle” home page, and glance through its records of your web-surfing history.

Ah, you are thinking, it’s that paranoid Rowan again, the hack who anonymised his Oystercard so the radio tags could never locate him, and who web-surfs using Google “proxy” alternatives such as Scroogle.org. Yes, I can see that Google’s vision is nothing more Orwellian than to be the dominant provider of personalised advertising. But we are choosing to surrender our privacy without considering what we are getting out of the deal.

This is no quirky start-up now, but a global giant reaching more than a billion people, with an unhealthy dominance in both information sourcing and advertising sales. Its proposed $3.1 billion acquisition of DoubleClick, the leading digital ad-serving business, gives a worrying indication of its corporate thinking. By combining both companies’ data systems it can know not only what you are searching for, but, thanks to DoubleClick’s ubiquitous “cookies”, which websites you are visiting. The official line will doubtless be that data will be anonymised, and that the combined company will obey the law. Funny: DoubleClick also made such assurances about privacy protection, until seven years ago its CEO was forced to admit that the company made a “mistake by planning to merge names with anonymous user activity across websites in the absence of government and industry privacy standards”. In other words, knowingly broke the rules.

Google is also working to build up “psychological profiles” of individual web users, in order to sell that personally linked information to advertisers. According to a recent patent application, the company intends to monitor players of online games in order to characterise them in categories such as cautious, risk-taker, stealthy, honest – labels that the dishonest will doubtless hope never reach prospective employers. Then there is its recent $3.9 million investment in 23andMe, a company that wants to help us to explore our DNA online. Hmm, just how useful would it be to an insurer to cross-match your genetic profile with all your illness-related web searches?

The question its users must urgently ask is how far they trust Google to protect their information. Until now, its arrogance has not been matched by any clear evidence that privacy will be guaranteed. Even after the company belatedly clarified in March that it will typically hold user search data for no more than two years, it does not make it easy for us to know what it does with our secrets.

Google has proved the decade’s most innovative, creative and astute new business. Now it needs to be reminded that, just as Microsoft’s dominance was eventually challenged in the courts, even the biggest conduit to the world’s information will be restrained by government for the consumer’s greater good. That is, once the consumer realises what he or she has just given up for ever.

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