A somewhat vague term generally referring to software that is secretly installed on a user's computer and that monitors use of the computer in some way without the users' knowledge or consent.
Most spyware tries to get the user to view advertising and/or particular web pages. Some spyware also sends information about the user to another machine over the Internet.
Spyware is usually installed without a users' knowledge as part of the installation of other software, especially software such as music sharing software obtained via download.
