META-engines

Earlier in this course we have stated that Meta search engines are another approach to search data offered on the World-Wide Web.

What is a Meta search engine? It is a search tool that doesn't create its own database of information. Instead, Meta search engines utilize multi-engine search, or a meta-search engine that combines results from a number of search engines at the same time and lays them out in a formatted result page. Metacrowler is a system that crawls the Web by follow links. This method of using multiple databases makes search results more comprehensive, but slows results.

A common or natural language request is translated to multiple search engines, each directed to find information the searcher requested. The search engine's responses thus obtained are gathered into a single result list. This search type allows the user to cover a great deal of material in a very efficient way, retaining tolerance for imprecise search questions or keywords.




How META search engines work
1 . How Meta search engines work

Some may believe that Google or Yahoo! index every Web page, that's not the case. Actually, there are many reasons, on-page and off-page factors, why one search engine may index one page and not another. That's where Meta search engines become interesting as they can address index data centers of multiple engines.

In short, a Meta search engine is an engine that gets listings from two or more other search engines, rather than using its own resources and tools.

Examples of multi-engines are MetaCrawler (http://www.metacrawler.com) The Mother of all Search Engines (http://www.mamma.com/). MetaCrawler refers your search to seven of the most popular search engines (including AltaVista and Lycos), then compiles and ranks the results for you. Of course there are more Meta search engines. Like most tools, they don't work in all situations. But it's a good idea to experiment with these services the next time you search.
Clusty http://www.clusty.com/

Sources: Ask, GigaBlast, LookSmart, Lycos, Live Search, MSN.com portal, Open Directory, Special databases (New York Times, AP, Wikipedia) , WiseNut

Dogpile http://www.dogpile.com/

Sources: Google, Yahoo!, Ask and About

ez2Find http://www.ez2find.com/

Sources: Google, AlltheWeb, Altavista, Live Search, Yahoo! and Ask.

Killer Info http://www.killerinfo.com/


Sources: AOL, Google, Yahoo!, Live Search, FAST, Lycos, AltaVista, Wisenut, LookSmart and DMOZ.
What you should remember from this lesson:

A Meta search engine is an engine that gathers listings from two or more other search engines, rather than using its own resources and tools.