Meta search offered by a number of specialized search engines, including Dogpile, KartOO, Excite, Mamma, and ProFusion is the concept of simultaneously engaging multiple search engines and having each of the source engines return its own list of results for a given keyword, thus, theoretically, providing more comprehensive results than regular Web searches.
Most meta-search engines display the combined search results on one prioritized list, which might mix listings from several sources. Other meta-search engines present each source search engine's search results separately, so that the user not only can tell exactly which results each individual engine returned, but also how each one ranked the results.
