Different Engines, Different Results

In April 2005, Dogpile.com collaborated with researchers from the University of Pittsburgh and the Pennsylvania State University to measure the overlap and ranking differences of the leading Web search engines in order to gauge the benefits of using a metasearch engine to search the Web.
The study evaluated the search results from 10,316 random user-defined queries across a sample of search sites; the results found that only 3.2% of first page search results were the same across the top three search engines for a given query.