Google and other public search engines offer quick and freely available information. But how much of the web do they actually search? Estimates are around 30%. The rest of the Internet has been referred to as the dark, deep, or invisible web. "More than half of the deep Web content resides in topic-specific databases" (Bergman) such as the databases provided to you by the UK Libraries.
Graphic design by Chris Worland. Graphic based on:
Bergman, Michael K. “The Deep Web: Surfacing Hidden Value.” Journal of Electronic Publishing Online-Only Journal 7.2 (2001): n.pag. Web. 8 August 2011. <http://hdl.handle.net/2027/spo.3336451.0007.104>
Devine, Jane, and Francine Egger-Sider. Going Beyond Google: The Invisible Web in Learning and Teaching. New York: Neal-Schuman Publishers, 2009. Print.
Gil, Paul. “What is the ‘Invisible Web’?” About.com. The New York Times Company, December 2010. Web. 8 August 2011. <http://netforbeginners.about.com/cs/secondaryweb1/a/secondaryweb.htm>
He, Bin, Mitesh Patel, Zhen Zhang, and Kevin Chen Chuan Chang. “Accessing the Deep Web.” Communications of the ACM 50.5 (2007): 94-101. ACM Digital Library. Web. 8 August 2011.