Poorly written spyware programs can, and often do, cause PC crashes and network slowdowns. Sending all this data back to the database also takes time and consumes network bandwidth, thus slowing down your Web surfing and emailing (and costing you money, if you're paying for network bandwidth according to total or peak usage).

And some spyware is particularly malicious. For example a web site called Lover Spy will, for $89, send email to 5 of your current or former partners inviting them to click on a Web page to read an online message about how much you still miss them. When the recipient installs the free program necessary to display the card, it also plants spyware which records all their keystrokes and passwords and emails them to you. It even installs a remote control application allowing you full access to their computer via the Internet.

Spyware can cost you serious money, too. In the US recently, an investment broker lost $40,000 after installing what he thought was a market analysis program but which turned out to be a transmitting his account login details to hackers.

Spyware is already a big problem around the world. In Europe, 1 in 3 companies has detected spyware on its network. And the typical spyware program is prolific, typically transmitting 300 items of personal information, totalling some 1 MB of data, from each infected machine every day.

So which software includes spyware? Among the most prolific offenders are the file sharing and swapping sites such as Kazaa, which are used by millions of Internet users to exchange files such as music and videos. The Kazaa software also includes a number of spyware programs which monitor your use of the system and help the company present you with targeted advertising in order to finance the free service.


At present, the legal situation regarding installing spyware without the computer user's permission is a grey area. There is, though, a move afoot in the US to force software authors to declare up-front if installing their program will also install spyware. Many programs do already do this, but the details are buried in the small print of a long, complicated online licence agreement that most people agree to with a single click and without bothering to read.

If you're worried about spyware on your PCs, here are our top tips for dealing with the problem.

1. Software authors often go to considerable lengths to hide the fact that their products include spyware, so it may not be immediately obvious whether there's any on your PC. Check the small print of the licence agreement before installing any freeware or shareware.

2. Get into the habit of uninstalling any software that you don't regularly use.