Below you will find a ranked list of metasearch tools which search multiple tools simultaneously. When metasearching, be aware that a metasearch is executed without taking advantage of specific designs and features of the individual search tools. The key to using metasearchers is finding the ones that eliminate duplicates and display in order of relevance rather than by specific search tools.
Ixquick is a comprehensive metasearcher that queries 14 search tools. Results are ranked by relevancy with information about which search tool the site came from. Ixquick allows keyword searches, natural language searches, and advanced boolean searches. Pages found in multiple engines are only listed once and ranked by relevancy. Ixquick also has a language feature to for searching non-English sites. Specialized searching includes images, news, and MP3.
Dogpile does metasearches in Alta Vista, Yahoo, Lycos, Excite, WebCrawler, InfoSeek, HotBot, and others. Dogpile presents results from each of the search engines it queries individually, instead of mixing them all together into a single list. While some love this feature, others find it difficult and less useful.
Yippy is a search tool that was formarly called Clusty. Results are subdivided into topics or "clouds" that groups similar sites.
Search.com was the former SavvySearch, but it bears no resemblance to its predecessor. Search.com follows a fairly common interface that is simple to use with both a metasearch feature or a browsable directory. Search.com retrieves results from Google, Ask Jeeves, LookSmart, AltaVista, MSN Search, and others.
Findelio, started in 2005, uses a simple interface to search multiple search engines--AllTheWeb, Bing, Exalead, and Entireweb. Findelio displays a directory listing after a search query.
Beaucoup is a link to more than categorized 1400 sites. Find sites for Searching, Reference, Literature, Computers, Internet, Media, Education, and more. Also offers geographic specific sites to search for worldwide information.
Monster Crawler searches the major search engines and combines the results after a list of advertised sites.
MetaEUREKA is a simple metasearcher from the Netherlands that provides results from major search tools. A portion of the results are set to retrieve advertisers.