With so many software and programs being created by computer programmers, its not a wonder how people get confused with meanings of different terms. The various terms used for these programs sometimes overlap in meaning, but let’s try to break the programs down into groups, each labeled, however arbitrarily, with one of the terms currently in use. Naturally there’s a good bit of overlap.
Adware like AdWare.Win32.AdWeb.f is the least offensive of the bunch, though still quite intrusive, annoying, and sometimes disruptive. These programs do anything from send dozens of unwanted ads to your browser — pop-ups, pop-unders, Flash animations that temporarily hijack your screen, you name it — to more direct assaults on your machine, including: resetting your home page, adding links in your Favorites, and yanking your browser to their sites while you’re trying to go elsewhere.
Some adware is perfectly above board, telling you up front that the software will direct ads to your display. One kind of browser, and one email client, offer no-cost, ad-supported versions of their programs, and require you to pay if you want to be ad-free; many other shareware developers offer similar versions of their wares. The more insidious ones install ad-channeling or tracking software without your knowledge. Often the data collected is used to “target” ads to the surfer, sending him advertisements tailored to his surfing habits. For example, if you visit several sites to peruse and download MP3s, this information will be sent back to the marketing company, resulting in them displaying MP3-related advertisements when you use the software.
Spyware is defined by Wikipedia as “technology that gathers information about a person and/or their computer, and transmits it to someone else: advertisers, law enforcement officials, hackers, etc.” It sends information on you and/or your machine back to its home servers, including IP addresses, email addresses, system configurations, and in some instances, credit card and personal information.