Spyware: Comparison

Spyware, adware and tracking

The term adware frequently refers to any software which displays advertisements, whether or not the user has consented. Programs such as the Eudora mail client display advertisements as an alternative to shareware registration fees. These classify as "adware" in the sense of advertising-supported software, but not as spyware. Adware in this form does not operate surreptitiously or mislead the user, and provides the user with a specific service.

Most adware is, in a sense, spyware: it displays advertisements related to what it finds from spying on you. Claria Corporation's Gator Software, for example, can be installed without your permission by visiting some web sites. You then start seeing many pop-up advertisements. Claria gets feedback from the spyware and directs revenue to the installing site and to Claria. Other spyware behavior, such as reporting on websites the user visits, occurs in the background. The data is used for "targeted" advertisement impressions.

Spyware has cast suspicion on other programs that track Web browsing for statistical or research purposes. The Alexa Toolbar, an Internet Explorer plug-in published by Amazon.com that gathers statistics to rate web site popularity, is sometimes considered to be spyware by anti-spyware programs.

Software bundled with free, advertising-supported programs such as P2P, also may act as spyware. This presents a dilemma for anti-spyware removal tools, which may inadvertently disable wanted programs by removing the spyware component. To address this dilemma, the Anti-Spyware Coalition is trying to get consensus across the anti-spyware industry, regarding what is and isn't acceptable software behavior. This group of anti-spyware companies, academics, and consumer groups have collectively published a series of documents including a definition of spyware, risk model, and best practices document.

Spyware, virus and worm

Unlike viruses and worms, spyware does not usually self-replicate. Like many recent viruses; however, spyware exploits infected computers for commercial gain. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements; theft of personal information (including financial information such as credit card numbers); monitoring of Web-browsing activity for marketing purposes; or routing of HTTP requests to advertising sites.

Adware and spyware are similar to viruses in that they can be malicious in nature, however, people are now profitting from these threats making them ever more prevelant.