In general, spyware is any technology that aids 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. Spyware can get in a computer as a software virus or as the result of installing a new program. Data collecting programs that are installed with the user's knowledge are not, properly speaking, spyware, if the user fully understands what data is being collected and with whom it is being shared.
Spyware is part of an overall public concern about privacy on the Internet.
Millions of people are using advertising supported "spyware" products and could not care less about the privacy hype..., in fact some "spyware" programs are among the most popular downloads on the Internet.