"Each search engine has its own method of searching and each will return different results. Dogpile looks at all of them, decides which are most relevant to your search, eliminates duplicates and reveals them to you. In the end, you get a list of results more complete than anywhere else on the Web."
"MetaCrawler.com utilizes metasearch technology to compile results from many of the Web's major search properties, delivering more relevant and comprehensive results every time you search. By accessing multiple search engines for each query, MetaCrawler.com provides you with a richer and more relevant spectrum of results than you would from using any single search engine."