You may, or may not, have heard of metasearch engines. For some, they are the most comprehensive means of searching the web, for others, they consider them to be unreliable.

The metasearch engine, as the name suggests is a type of search engine used for searching the web. They are different from more standard search engines, in that they send user requests to multiple search engines (possibly databases) and display the results in a single list or source.

By doing this, the user can enter a single search and gain access to a number of search engines simultaneously. This can also benefit the user, as they may not have to make use of other search engines separately.

Their basic operation is based on a principle of virtual databases. No physical catalogue of the web is compiled, but instead, the user request is passed on to other databases and compiled homogeneously, based on the specific algorithm.

Metasearch engines are not exactly alike. For example, while some may use the bigger search engines others do not, and search lesser-known search engines, newsgroups or databases for results.

How the results are displayed can also differ. While some will display results according to the search engine or database, others sort results into relevance, and even conceal which search engines returned the results.

These search engines can also make use of different search parameters. While the word AND is used with some, others require the plus sign or just spaces to be used for search combinations.

There are a number of metasearch engines available for use on the web. A good example is Dogpile, which uses more popular search engines. Meta Crawler, Web Crawler, HotBot, Clutsy, SideStep, Mobissimo and MetaLib are also good examples of variable metasearch engines.

With regard to the quality of results, they can be variable. One advantage of metasearch engines generally, is that they allow for more comprehensive searches than any stand-alone web server does. As such, they may well generate a larger number of page finds.

However, how relevant these results will be is questionable. As they are less specific than stand-alone search engines, their results can be less relevant since they cannot directly access the databases.

For this reason, metasearch engines are perhaps not as widely used as the stand-along search engines like Google. While they are good for providing more comprehensive web searches, some of the results can be irrelevant.

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