Wikipedia defines a meta-search engine as a search engine that sends user requests to several other search engines and databases and aggregates the results into a single list or displays them according to their source.
MetaCrawler – Uses innovative metasearch technology to search the Internet’s top search engines, including Google, Yahoo! Search, MSN Search, Ask Jeeves, About, MIVA, LookSmart and more. Search refinement available.
Dogpile -Puts the power [of] all the leading search engines together in one search box to deliver the best-combined results. Toolbar download available.
Mamma – “The mother of all search engines” – a discount and coupon code search engine.
IxQuick – “The world’s most powerful metasearch engine,” includes universal power search, global search, and search refinement. Toolbar download available.
kartOO – A visual meta search engine that instead of showing up traditional search results pages, displays a graphical map of search results. Honestly, I don’t get the point.
Ithaki – Search various search engines and ranks results based on an internal ranking system.
Seekz – A parallel web search engine that queries many of the Internet’s top search engines and displays results in groups with the most relevant website appearing first. Removes duplicate results as well.
iBoogie – Puts documents with similar content or with related topics into the same group. Each group is assigned a label based on the content of the documents.
Zuula – Provides search unaltered search results from various search engines giving users the chance to check them first before going to results from individual search engines. And it even remembers which search engine you have been to so you can easily switch back and forth. Sponsored links are separated.
inCrawler – A metasearch engine and a web directory in one. Works like your traditional search portal where categories are displayed upfront just below the search toolbox.
WindSeek – Pulls results from many of the major search engines simultaneously with lightning speed and accuracy.
Seek2Day – Gathers results from 17 different major search engines and in a very quick way decides which information is most relevant to the user. The results are then presented in a comprehensive format.