masthead for Beyond Google: The Invisible Web with a spiderweb next to it

What is the Invisible Web?

Traditional definition
    "Invisible Web" is the term used to describe all of the information available on the World Wide Web that cannot be found by using general-purpose search engines.

(Devine and Egger-Sider, 2001)

Cognitive definition
    The Invisible Web represents resources that cannot be found because of searchers' limited research skills.

(Devine and Egger-Sider, 2013)

Updated December 2014