Spyware is.....

There are concerns that some Web sites and commercial organisations track users' online activity through the use of what is called ‘spyware'. Usually coming in the form of ‘cookies' - these enable the cookie writer to build-up information about what you do and where you go on the Web. Software is available that checks for and removes spyware.

A technology that assists in gathering information about a person or organization without their knowledge. On the Internet, "spyware is programming that is put in someone's computer to secretly gather information about the user and relay it to advertisers or other interested parties." As such, spyware is cause for public concern about privacy on the Internet.