A meta search engine is a search engine that queries many different search engines and combines the results from all of them, or else displays the results separately but in one place. A meta search engine does not actually crawl the web itself, like a real search engine, instead relying on data gathered by other search engines. The meta search engine has been around almost as long as search engines themselves, and some people find them preferable to using a single search engine, as they allow for a wider range of results.

The earliest widely-successful meta search engine was MetaCrawler, launched in 1995 at the University of Washington. MetaCrawler searches many of the top search engines, including Google, MSN, Ask Jeeves, About, Yahoo!, and LookSmart. The meta search engine was purchased by InfoSpace in 1997, and joined the InfoSpace network in 2000. Although it hasn’t changed much over the years, MetaCrawler continues to be one of the most popular meta engines, likely because of its age.

A number of traditional search engines have transformed into meta engines over the years, as well. WebCrawler, for example, is now a meta search engine, although it began its life as a real search engine that crawled the web, when it was owned by Excite. InfoSpace also purchased WebCrawler, and turned it into a meta search engine, not long after MetaCrawler became part of the InfoSpace network, and around the same time the Excite search engine itself was bought by them and also transformed into a meta search engine.

One of the most popular meta engines in the past was DogPile, which won the Best Meta Search Engine award in 2003. DogPile allows for a great deal of customization, allowing users to choose exactly what search engines they want to be included in their meta search. DogPile also added a number of specialty search features, such as a yellow pages search when relevant, to make the meta search even more useful to users.

In recent years, the meta search engine has transformed from being a simple collection of search results, into formatting them into new and innovative ways. KartOO, for example, connects the results by keywords, creating a visual cluster map, which allows the user to find the area of interest and narrow their searches based on that. Clusty, owned by meta search engine pioneer Vivisimo, is another that tries to differentiate itself based on its results and how they’re organized. Clusty bills itself as a Web 2.0 meta search engine, and utilizes Clusters, which are categories to the side of the search results that can help users drill down to the exact web space they want to be searching within.

The meta search engine has evolved quite a bit over the past decade, and it is likely it will continue to evolve over the next decade as well. The search market is a lucrative one, and the meta search engine offers an opportunity to enter the market without having to try to compete directly with crawling engines like Google or Yahoo! which have substantial resources at their disposal and a strong head start.