Meta search engine

According to wiki, A metasearch engine is a search tool that sends user requests to several other search engines and/or databases and aggregates the results into a single list or displays them according to their source. Metasearch engines enable users to enter search criteria once and access several search engines simultaneously. Metasearch engines operate on the premise that the Web is too large for any one search engine to index it all and that more comprehensive search results can be obtained by combining the results from several search engines. This also may save the user from having to use multiple search engines separately.

Metasearch engines create what is known as a virtual database. They do not compile a physical database or catalogue of the web. Instead, they take a user’s request, pass it to several other heterogeneous databases and then compile the results in a homogeneous manner based on a specific algorithm.

Here are several hot Meta Search engines:

• http://www.metasearchengine.com/
  Meta Search Engine.com makes it easy to search the Web, since it has all the best search engines combined into one.
• http://www.mamma.com/
  Mamma.com is a global Meta search engine. It provides extensive web search and fetches results from top search engines.