are collections of Web sites that people have selected and organized. They have arranged a small percentage of Web sites into subject categories and sub-categories. Sometimes links are annotated so you'll know before clicking on it what a site contains.
subject directories, such as the Yahoo! subject directory, also have a search engine function. Other commercial subject directories include About.com and the Google Directory. There are also specialized subject directories created by libraries and publishers. These include ipl2 and Infomine.
Directories used to be a common way to search for Web sites, but now many people just go straight to a regular search engine. A subject directory still might be nice for certain broad topics.