There are basic skills required to successfully navigate searches of the 'web'. Some seach engines employ directories, and some directories use search engines. Yahoo' is one such service. Think of it as going to a library, where every book has been selected by a librarian. Just as libraries have a relatively small portion of all the books ever published, directories have just a segment of the Web sites out there.
Search engines are services that scan the Web in various ways for Web pages.
Hotbot' is an example of a search engine. There are also hybrid search engines, such as 'Infoseek', that combine both staff-reviewed sites with search engine results. Another way to search is to use a 'metasearch' engine. This is a service that sends your search out to several search engines at the same time. One of these 'meta' search engines is 'Dogpile'.