A few examples of common spyware programs may serve to illustrate the diversity of behaviors found in these attacks.
- Caveat: As with computer viruses, researchers give names to spyware programs which frequently do not relate to any names that the spyware-writers use. Researchers may group programs into “families” based not on shared program code, but on common behaviors, or by “following the money” or apparent financial or business connections. For instance, a number of the spyware programs distributed by Claria are collectively known as “Gator”. Likewise, programs which are frequently installed together may be described as parts of the same spyware package, even if they function separately.
- CoolWebSearch, a group of programs, installs through the exploitation of Internet Explorer vulnerabilities. The programs direct traffic to advertisements on Web sites including coolwebsearch.com. To this end, they display pop-up ads, rewrite search engine results, and alter the infected computer’s hosts file to direct DNS lookups to these sites. 
- Internet Optimizer, also known as DyFuCa, redirects Internet Explorer error pages to advertising. When users follow a broken link or enter an erroneous URL, they see a page of advertisements. However, because password-protected Web sites (HTTP Basic authentication) use the same mechanism as HTTP errors, Internet Optimizer makes it impossible for the user to access password-protected sites. 
- 180 Solutions transmits extensive information to advertisers about the Web sites which users visit. It also alters HTTP requests for affiliate advertisements linked from a Web site, so that the advertisements make unearned profit for the 180 Solutions company. It opens pop-up ads that cover over the Web sites of competing companies. 
- HuntBar, aka WinTools or Adware.Websearch, is a small family of spyware programs distributed by Traffic Syndicate.  It is installed by ActiveX drive-by download at affiliate Web sites, or by advertisements displayed by other spyware programs—an example of how spyware can install more spyware. These programs add toolbars to Internet Explorer, track Web browsing behavior, redirect affiliate references, and display advertisements.