Yahoo! is the world's biggest directory. And Google is probably the world's biggest search engine.Directories work differently from search engines. While a search engine will spider and index your page, analyzing it on different things such as keyword density and link popularity, a directory does none of this. Instead sites need to be submitting manually to them, and then also edited manually by an editor. Once you are accepted into the directory it doesn't always mean you'll be getting good traffic right away. Instead it could take a wait of two weeks or more before the search engines that are powered by the directories update their listings.Directories maintain ordered lists of websites.