Do Search Engines Suppress Controversy? by Susan L Gerhart at Software Engineering and Computer Science, Embry-Riddle Aeronautical University (Nov 9, 2003)
Study team picked five topics with known controversies and ran searches to see if the results picked up the controversies. "("Belize", "distance learning", "Albert Einstein", "St. John's Wort", "female astronauts"). The results were mixed, 2 controversies showed and 3 were virtually missing when search results were plied from three popular engines (Google, Teoma, and AllTheWeb) and two meta-searchers (Profusion and Copernic, querying and collating from different engines). Most enlightening were the factors that suppressed or revealed the controversies."
Study concluded that "Search technology is biased to present the "sunny side" of topics. You have to search harder for the "dark side".