- Even the best search engines can access only about 16% of the available information on the World Wide Web. Therefore 84% of the information is excluded. That 84% has become known as the Invisible Web.
- Put another way, the size of the Invisible Web is 500 times larger than the Surface Web.
- The Invisible Web contains nearly 550 billion individual documents as compared with the Surface Web's 1 billion.
- The Invisible Web is the largest growing category of new information on the Web.
- 95% of the Invisible Web is publicly accessible information.
- More than half of the Invisible Web resides in topic specific databases.
- Surface Web: 167 terabytes
- Deep Web: 91,850 terabytes
- Academic Invisible Web between 20-100 billion documents
- 11+ billion static pages are hidden from the public as well as 450+ billion database-driven are completely invisible to Google
(Paul Gil 2013)
- "Trillions + pages of information" that current search engines cannot find
- "In fact, typical search engines like Google, Yahoo, or Bing actually access only a tiny fraction – estimated at 0.03% – of the internet."
(Ultimate Guide to the Invisible Web 2013)