The spy who came in from the web

Imagine if, whenever you sat at your computer, someone peered over your shoulder to see what websites you were visiting, who you were emailing, what you were typing and even made a note of your credit card details.

Now imagine that, instead of a person sitting beside you, there was software on your computer that carried out this spying.

Not only did it keep tabs on what you were up to, it used your internet connection to send the information to a secretive third party - all without your knowledge.

Welcome to reality. We've just described one of the sneakiest types of software in existence: spyware.

I Spy
Spyware - or 'adware' as it's more charitably known - is software that surreptitiously installs itself on your computer.

Once ensconced, it runs quietly in the background, covertly keeping an eye on what you're up to online: the websites you visit, the links you choose to click and so on.

The monitoring is ostensibly carried out to clarify your demographic and is then used for marketing purposes. But some spyware goes further; it looks at files on your hard disk, logs whatever you type and even paves the way for other software to be secretively installed.

Worse still, spyware hijacks your internet connection to report its findings back to its creators, who can then use the information for any purpose they choose.

Its clandestine nature also means that spyware is stealing your hard disk space and memory, and poorly written spyware applications can cause computer crashes.

So where does spyware come from and how can you find out whether some has wormed its way onto your computer? More importantly, how do you get rid of it?

Spies like us
Freeware, by its very definition, is free. Much of it is produced purely because programmers enjoy programming and like to give their work away. Some, however, is 'ad-supported'.

Usually, this means that you have to put up with a few flashing ad banners in the application's window but, in some cases, it can mean that you're getting more than you bargained for, namely spyware.

Most freeware comes with a licensing agreement and, although reading small print is about as fun as watching paint dry, it will usually highlight whether any spyware is installed.

Software providers are not legally required to provide this information though, so if your software has ad banners, there's a strong chance that it's using spyware too.

One of the most famous spyware cases concerned RealNetworks and its RealJukebox media player. By installing the player, RealNetworks was able to track what users were listening to, apparently so that it could market specific music to them.

Last year, the games company Mattel came under attack from concerned parents about spyware it was using.

A piece of software called 'Brodcast' was found in a number of interactive children's educational titles and was designed to collect personal information from users - mainly children - and pass it to Mattel.

Mattel ceased to use the software when the US passed the Children's Online Privacy Protection Act, a law that forbids websites or online services from collecting personal information from children under 13.

As freeware is widely distributed via the internet, spyware companies such as Radiate and Cydoor have seen it as a platform to promote their business. Software developers have also seen it as a way to generate revenue.

Adware kits are given to developers who then integrate banners and adverts into their software. The advert owner pays the adware company for promoting the ad and the adware company gives a cut to the developer.

Revenue is raised in CPT (cost per thousand). So every time your software displays an advert, you create an 'impression' and a thousand of these generates around £1 for the developer.

The spying game
Unfortunately, even if you know you have some spyware on your computer, getting rid of it isn't that easy.

It's not in the spyware company's interest to have its software removed, so you usually won't find an entry for it in Add/Remove Programs and you may not even find a folder within Program Files on your hard disk.

The first step to keep your PC free from unwelcome guests is prevention. Before you download and install any freeware or shareware, type in its name at the Spychecker website.

The site has a large database of ad-supported applications and will tell you whether an application is contaminated with spyware and where it's from. It will even link you to the host application developer's privacy statement.

Should you belatedly discover that you have unwittingly invited some spyware onto your computer, all is not lost.

The Lavasoft Ad-aware utility is free and not ad-supported. It will scan your PC for known spyware and whip it off in a trice. We found 79 active bits of spyware on one of our computers and Ad-aware expunged them all.

The spy who loved me
Computers and privacy go together like a horse and marriage, and the only person that can guarantee the privacy of your data is you.

The fact that many spyware applications are harmless marketing research tools is not the point; allow one piece of spyware into your computer and you could well be opening a floodgate.

Crumbs!
Spyware isn't the only thing on your computer that can be used to obtain demographic data. Cookies are as much part of the web experience as hyperlinks but few people are aware of their existence.

A cookie is simply a text file generated by a website and stored on your computer. It's used to keep track of your activity on a particular site, usually to make the site simpler to use when you go back to it.

Cookies track basic things such as how much time you spent at a site, which site you came from and which web browser you're using.

Some online shopping sites use cookies to make recommendations based on previous purchases and we at Computeractive use them to see which parts of our site are popular with you.

Cookies pose very little security threat and their benefits are usually worth any minor impact on privacy.

If you don't like the idea of anyone seeing what you do online though, there is a way of stopping cookies being used by your browser.

In Internet Explorer, go to the Tools menu and choose Internet Options. On the General tab, click on the Delete Cookies button to remove any existing cookies. Then click on the Privacy tab and move the slider to the Block All Cookies position.