Metasearch engine
A metasearch engine is a search engine, whose essential feature is that it forwards a query to several other search engines at the same time, collects the results and prepared. The results can be easily arranged in sequence. More commonly, partial complex post-processing, such as
- Aggregation of duplicates ( the same fund in multiple search engines is displayed only once, influencing the evaluation mechanism ),
- Rating and ranking of results,
- Search engine ranking,
- Clustering of results.
The results are usually uniform, in accordance with a search engine is illustrated.
Traditionally, the server is the metasearch engine has to wait for replies from all search services, to which he has passed the search to only then to proceed with the presentation of results. This results in delays compared to a normal search engine. To counteract this, each one carried out upon the arrival of different search results updated display or slow-reacting search engines can be excluded from the search.
The current generation of metasearch engines also allows syntax translations, so that even complex queries can be sent to the respective targeted search engines.
The first meta-search engine for the World Wide Web Erik Selberg and Oren 1995 programmed Etzioni as part of a research project at the University of Washington in the United States: MetaCrawler - Parallel Web Search Service. Developed in 1996 employees of the Regional Computing Centre for Lower Saxony ( RRZN ) under the direction of Wolfgang Sander- Beuermann MetaGer first German metasearch engine. Other well-known meta-search engines are Dogpile and Ixquick.
Some formerly independent search engines such as WebCrawler and the American edition of Excite, are now also working as a meta-search engines.
Colloquially also search collections are referred to as meta-search engines. The difference, however, that the results Show search collections in each individual external windows on the original surface of the respective search engine and metasearch engines do not merge as the results. These search collections, the part of the formerly also independent HotBot.
Legal admissibility
Following a decision of the ECJ metasearch engines are then illegally when a search engine of scanned comparable search form is available, the searches in "real time " are passed to merge the search result representation duplicates. Given the reasoning of the decision is the business model of meta-search engines but, like the other Datenananalysedienste into question