Spyware is Internet jargon for advertising-supported software. This type of software often automatically installs itself on your computer without your knowledge in order to collect your personal information and provide it to a website or advertiser. Spyware is hidden in the background and keeps track of your web browsing, what information you enter into forms and even the configuration of your hardware and software. The company receiving this information may use it directly or, more likely, will sell this information about you. Based on this information, you may begin to see incessant pop-up ads, giving the false impression that the Web page being viewed is responsible for the constant annoyances.
Spyware usually is usually hidden in or behind an application that you want to use (such as a music player). When you install the software, the spyware application also installs itself.
In addition to the annoyances of increased spam and advertising, the spyware application ties up valuable computing power and can eventually make it run slower. It can create conflicts with other software on your machine causing programs to lock up or causing your machine to crash. It can even be abused by hackers to steal your password or to take control of your computer.
If you load software from the Internet, read the license agreement carefully. Some companies actually disclose that they will install an application on to your computer and may allow you the option to "opt-out". For example, RealJukebox has the ability to track how you used the program including the number of recorded songs on the computer, the format that songs are recorded in, the user's musical preferences, the quality level of the recordings, and the type of portable player connected to the computer.
You can use specialized software to find and disable spyware applications and to protect your computer. Two of the better-known free-ware applications are SpyBot Search and Destroy and Ad-Aware. Whatever anti-spyware solution you pick, be sure to keep it updated and run it regularly.
Be sure to read all "End User License Agreements" very carefully and make sure you understand what is actually going to be installed on your home computer.