What is spyware, adware, and malware, and how does it get on my system?

Spyware is software that gathers information about you, your browsing and Internet usage habits, as well as other data. Adware is software that displays advertising banners, re-directs you to websites, and otherwise conducts advertising on your computer (not to be confused with popup ads, which come from the websites that you visit). Malware is malicious software that is intended to do harm to your computer or software. Malware includes viruses, Trojans, and worms.

Many users inadvertently download spyware or adware when downloading other programs. Many popular peer to peer applications and other software packages include adware or spyware packages. Even seemingly innocuous programs such as special cursors can contain spyware. In addition, many websites and advertising banners set cookies on your system that track your web usage.