Subject-Oriented Directories are browsable indexes of Web sites. One of the most common search directories is Yahoo.
Meta-Search Engines allow you to submit keywords in a search box, and it transmits your search simultaneously to several individual search engines and their databases of web pages. Within a few seconds, you get back results from all the search engines queried. Meta-search engines do not own a database of Web pages; they send your search terms to the databases maintained for other search engines.
Mamma http://www.mamma.com
Dogpile http://www.dogpile.com
Search http://www.search.com
Vivisimo' http://vivisimo.com
