Google

Google is the most popular search engine on the web.  Google indexes billions of Web pages, so that users can search for the information they desire, through the use of keywords and operators.  Google has also employed the Web Search technology into other search services, including Images Search, Google News, the price comparison site Google Product Search, the interactive Usenet archive Google Groups, Google Maps and more.

Google

Yahoo

A very good search engine, people remember it as a huge database of many topics from education to entertainment, from health to information about any region, city of a country.

Yahoo

LYCOS

Lycos frequently asked questions give a good explanation of how the search engine works.  Search results are presented with a lot of information about each site retrieved so that a decision can be made about  relevance of the site without having to jump to that site.

Lycos

Web crawler

Web crawler is a search engine that provides very good explanations in an indexed format, Content of sites, indexed as well as files and URL’s are mentioned as the results.

webcrawler