Computer software that gathers user information, usually for advertising purposes, without the knowledge or informed consent of the user. Spyware generally finds its way onto computers as programs covertly bundled with downloaded software, or else as a result of browsing dubious websites. Spyware can monitor a user's web activity, scan files, create pop up ads, log keystrokes, change the default page on the web browser, and even gather password and credit card information. Spyware technology is constantly evolving, but most spyware removal programs are continually updated to keep pace with the latest variations.