There are different kinds of search engines namely: the World Wide Web, Meta Search, White Pages and News Group.
The World Wide Web search engines are used for finding web documents. Google and Yahoo are examples of world wide web search engines.
The Meta Search is a search tool that sends user requests to several other search engines and databases and presents them to you on a single screen. Rapidshare Search is an example of meta search.
White Pages services are used for finding e-mail addresses, business listings, and telephone numbers.
Newsgroup search engines can help you find general ideas or discussions on specific topics such as religion, gun control, animal rights, the death penalty, politics or race relations.