Second site: Cookie monsters

IT HAS a population of over 35 million, putting it in the same league as Spain or Argentina. But few of its subjects are aware they belong to it, and its government swears that it doesn't know who any of them are. This virtual nation, called Engage Knowledge, is a database created by Engage Technologies, through a technique called "behavioural profiling". It has been amassed in pursuit of marketing's Holy Grail, the capacity to match customers and sellers with perfect efficiency.

"One-to-one" marketing involves precision-guided advertising, which relies upon accurate knowledge of individuals' tastes and spending patterns. With its obsessive propensity to record every move that is made within it, the Internet fosters the illusion that marketing can be transformed into a precise science. What sites you visit, what pages you look at within them, the path you take, how long you spend at any particular place; all these can be logged and charted to form your permanent record. Engage's new AudienceNet advertising network delivers Web ads on the basis of profiles like these. It'll be no good trying to defy consumer stereotypes by wearing Dockers but watching MTV. The system will track you down.

Its foot in your door is known as the cookie. This is a tiny file sent to your computer, where it lodges inside your browser. Some cookies do useful things like storing passwords, so that you don't have to remember them when you return to sites such as newspaper archives, which often require registration. They are also ideal for tracking, since they can identify an individual computer by a code number.

Many people dislike cookies on principle. Up-to-date browsers make it easy for the user to delete cookies or refuse to accept them, or at least issue a warning before they are delivered. (A website called Cookie Central offers free software for dealing with cookies in older browsers.) Even if you are content to have them, you can at least get an idea of who has been leaving things on your hard drive. If the cookie list contains one called "CyberGlobalAnonymous", you are part of Engage Knowledge. And you will almost certainly find a deposit labelled "doubleclick", which is to cookie caches what woodlice are to the undersides of stones.

Like AudienceNet, DoubleClick manages the advertisements which appear on other sites' pages. It uses cookies to ensure that individuals don't see the same ads on every site they visit. Like other tracking organisations, it has posted a privacy statement on its own website, emphasising that it works mainly by collecting information that cannot identify individuals. But personal information is gathered in vast quantities across the Net, largely by registration and purchasing forms. At present, individuals have little more than the word of website operators that personal and anonymous information is not being merged.

Privacy policies and privacy organisations have become an online industry in themselves, representing the strenuous efforts of the commercial Web to head off regulation by the US government. Their fundamental weakness is illustrated right at the end of DoubleClick's small print, where it notes that it is planning to merge with a company that owns a database of personal information. If DoubleClick ever decides to combine this with its own database, it remarks in its lawyerly way, it will revise its policy accordingly. In other words, it reserves the right to move the goalposts. And since most people don't even know they've been DoubleClicked, very few are likely to notice.

If it makes its own rules, the industry can always stay ahead. Without government regulation, we may end up taking the advice of Scott McNealy, head of Sun Microsystems, a member of the Online Privacy Alliance: "You have zero privacy anyway. Get over it."