HijackThis lists the contents of key areas of the registry and hard drive--areas that are used by both legitimate programmers and hijackers. The program is continually updated to detect and remove new hijacks. It does not target specific programs and URLs, just the methods used by hijackers to force you onto their sites. As a result, false positives are imminent, and unless you're sure about what you're doing, you should always consult with knowledgable folks before deleting anything.