Book review: The Filter Bubble: What the Internet is Hiding from You by Eli Pariser

Signing up to Facebook appears to offer us the unlimited opportunities to make contact with anyone or anything anywhere in the world. Schools, workplaces, shops , charities - everyone uses social networking sites. They help us keep in touch with friends and family members, allow us to swap news, photographs, videos, links and other information . All this is available 24/7 , and it's free. What's not to like?

First of all, says Eli Pariser, you should work out just why it is free. "If you're not paying for something, you're not the customer, you're the product being sold," he points out.

Of course most people are well aware that simply logging on makes us available consumers, hence the endless emails from online stores, simply because we forgot to tick the box to say we didn't want them. But more worrying is the extent to which our details are being catalogued. Suddenly all those endless and bizarre requests from obscure relatives to join in playing Farmville, True Age Test, take part in the Nicest Person Contest, or start to build Family Trees take on a more significant meaning.

They're no longer minor irritations that assault your space as you squabble with friends or relatives over the latest football result, share a joke, or organise a social outing. They are there to Hoover up as much detailed information as possible: who you are linked up to, when, what their interests are, what relationships they have with others, what information you are exchanging.

Even clicking "No" can yield commercial information. There are programmes already operating which will provide commercial organisations with the details of how many times you click "no" before finally, out of irritation, or boredom you decide to click "yes". By matching this information with the tone of any messages or emails you're sending at the time, some of these programmes can determine not only when you buy things, but what your mood is when you do. Do you buy yourself something when you are feeling happy or just to cheer you up when you're feeling depressed? Do you buy when you're angry? To anyone with anything to sell, these are facts worth paying for.

Pariser writes: "Gmail and Facebook are extremely effective voracious extraction engines into which we pour the most intimate details of our lives." Those wallpaper options that we innocently select for our home page (grass, wood, seascapes) are being recorded and replicated as the backgrounds used by advertisers who target us for their products.The tone of a shirt advert sent to me will be completely different to the one sent to a friend with a different selection, although the product is the same.

And that's just the starting point. Having established who we are and our likes and dislikes, programmers are keen to mould who we become. If you are using Google, Pariser points out, the information you received is neither random nor comprehensive. There is no standard Google any more. Every search and click determines the content we will receive next time we log on.

This can not only be incredibly useful, it can also be extremely limiting. As Pariser points out: "Google is great at finding what we know we want but not at finding out what we don't know we want".

As an example he points out that because what we searched and read before filters what is offered next time, over a period of time the query "stem cells" will produce diametrically opposed results for scientists who support stem cell research and activists who oppose it. And when such a filter is extrapolated out through all the information received and exchanged across the internet, the world begins to become smaller, rather than larger. It is through diversity and open communication, says Pariser, that we heal the differences we perceive between ourselves and others.

But is Pariser a neutral observer in this debate? The fact that he runs the site MoveOn.org, which lobbies for effective consumer control over this type of information, makes one wonder.

Certainly, his book is primarily targeted at an American readership: in the UK and Europe, legislation allows us far greater access to our data and the opportunity to amend and correct it. There are also personal filters we can activate (if we have the time and inclination to find them) which limit the amount of information we reveal.

This aside, Pariser's book is well written, thoroughly researched and informative. Having documented the changing virtual world we live in, he goes on to explore what might happen next. And this is when the possibilities become truly amazing - or, if you prefer, scary.

We won't just be targeted online. Linked to our GPS phones, rolling poster ads will identify us and deliver a specific message to us as we walk down the street past a bus shelter. On a personal level, face recognition from social networking sites will even identify possible partners for us when we walk into a bar or restaurant.

If the people who create the algorithms behind the social networks are now in charge of the world, we need to be conscious of who they are. They might, says Pariser, start out as archetypal computer geek teenagers, isolated from society but spending hours hacking and experimenting with code. Obsession often follows, as occasionally might great financial reward.What doesn't follow quite as regularly, he argues, is social responsibility, yet those who know how code works and what it does have a duty to society to use it in an altruistic fashion, in much the same way that early industrialists like Robert Owen in New Lanark and the Quaker families used part of their profits to create housing, schools and improve the quality of life for their workers. Historically, those who achieved such power did so later in life, as rounded individuals with a wealth of life experience. That mightn't happen this time.

We may have moved a long way from Picasso's assertion that "Computers are useless, they can only give you answers, they cannot ask questions". The questions computers ask of us without us being aware of it may be the most worrying of all.