Call it better marketing or call it an intrusion of privacy but most people, I would bet, are unaware that their Internet surfing and purchasing habits are being electronically tracked while they spend time downloading information or buying goods.

And with the recent purchase by DoubleClick Inc. (www.doubleclick.com) of Abacus Direct Corp. computerised tracking is going to get more precise and intrusive this year.

DoubleClick is the Internet's largest advertising company. Abacus is a direct marketer that maintains a database of names, addresses, telephone numbers and retail purchasing habits of 90 percent of American households.

And since e-commerce is worldwide business, those living outside the US can also expect their clicks to be tracked. But why should you care? After all, better marketing will mean the next time you go to your favourite site, your assumed preferences, based on your past habits, will load on to your browser and advertising suited to your tastes will pop on to the screen as you move about. The targeting could actually save you time and effort.

Yet we should be worried and on our guard, at least a little bit. What I worry about is not so much the fact that advertising companies like DoubleClick.com are tracking people, but that they are doing so without full disclosure of how the information is being collected, when it's being collected, and for what use.

The issue has raised a furore among privacy watchdogs who believe the new tracking technology has gone too far. Their hackles were raised after the DoubleClick purchase of Abacus.

Previously DoubleClick's database of 80 million online profiles were anonymous. With the Abacus database DoubleClick can start building a database with names attached.

The company has proudly proclaimed to its clients, the online retailers and advertising companies, that it will have built five to 10 million such profiles by the end of the year.

Such profiling potentially gives marketers the ability to determine the identity and preferences of the person visiting any one of the 11,500 sites that use DoubleClick's ad-tracking ''cookies''.

A cookie is a data file, in the form of a string of numbers and letters in a text file, that Web sites embed on a user's browser, and which can be used to track visitors as they move through the site.

As an exercise, go into your browser, say Internet Explorer, and open up the "Internet Options'' under the "Tools'' menu. Under the "General'' option click on the "Settings'' of the "Temporary Internet Folder'' and then "View Files''.

Even if your browser's "Options'' is set to clean out your "Cache'' folder, where all pages you surf to are stored on your computer, the cookies will generally remain in place unless you actually view the files in your Temporary Internet Folder, then select and delete them.

Marketing techniques, such as "collaborative filtering'', will let companies determine which ads pop up on your screen, but also alter content on the fly.

Collaborative filtering, which has become a more powerful tool through the use of computer software and databases, uses the technique of sifting through the millions of choices people have made before you.

The software is then able to make a decision about your preferences, no matter how disparate these may be.

For example a person who bought exercise equipment at the SkyMall site also received a pitch for hickory-smoked hams based on the preferences of customers who had made similar choices before them.

Amazon.com and Ticketmaster also use collaborative filtering to make recommendations. One of the best articles on collaborative filtering appeared in the New Yorker October 4, 1999 issue. Get a copy of ''The Science of the Sleeper'' by Malcolm Gladwell if you can.

"Marketers now play an elaborate game of stereotyping,'' Mr. Gladwell writes.

''They create fixed sets of groups -- middle-class-suburban, young-urban-professional, inner-city-working-class, rural-religious, and so on -- and then find out enough about us to fit us into one of these groups.

The collaborative-filtering process, on the other hand, starts with who we are, than derives our cultural "neighourhood'' from those facts. And these groups aren't permanent''.

To check out how powerful a tool collaborative filtering can be visit a research site called MovieLens (www.movielens.umn.edu) run by John Riedl, a University of Minnesota computer scientist.

After I rated a series of movies I had seen on a scale of one to five based on whether I liked them or not, I was then presented with ratings of other movies I might also like or dislike.

I found the site got more and more accurate as I was presented with various lists in different genres.

Computer scientist Ken Goldberg at Berkeley has also put up a similar site for joke preferences called Jester to check the pulse of your "sense of humour''.

But while Mr. Gladwell of the New Yorker sees collaborative filtering as having a "transformative potential'' in helping consumers more easily find the kinds of books and movies they might like, others, such as those who belong to the Electronic Privacy Information Centre and the Centre for Democracy and Technology (CDT), find the technology potentially dangerous.

"While the concern raised by the use of information about the individual to alter what information they see in the context of advertising may appear relatively trivial, this same practice, and perhaps data, can be used to make other decisions about the individual that even a privacy-sceptic may find objectionable,'' the CDT declares on its site (www.cdt.org).

"The info collected about the individual could be used to alter the prices at which goods or services, including important services such as life and health insurance, are offered, employed by a government, and could be used to alter the information viewed by individuals.'' While such a prediction may seem overly paranoid, don't forget that it was groups such as the CDT which helped stop Intel from embedding unique identifier codes on its first batch of Pentium III Processors.

E-commerce tracking a cause for concern Such identifiers would have made the process of collecting personal information through the Internet much easier.

CDT has now launched a campaign against DoubleClick to get the company to reveal how the new information database is going to be used.

Such moves by Intel and DoubleClick means we as consumers are going to have to be a little more careful about how the new marketing technology, no matter how useful, is going to be used on the Internet.

Tech Tattle deals with topics relating to technology. Contact Ahmed at ahmedelamin yhotmail.com or (01133) 467012599.