The document discusses the invisible web, also known as the deep or dark web. It states that the invisible web contains over 7,500 terabytes of information across 400-550 times more web pages than the approximately 1 trillion pages indexed by Google. The invisible web resides in databases, is dynamically generated, requires user registration to access, or is excluded from search engines by its owner. In contrast, the visible web can be found through general search engines. The document provides examples of the invisible web and recommends searching using the term "database" and limiting results by file type to find invisible documents. It also lists resources like the Wayback Machine that can be used to locate old web pages no longer indexed by search engines.

1. Discover the Invisible Web
Jeffrey Franklin and David Rakowski

3. What is the Invisible Web?
• a/k/a "hidden" "deep" and "dark" web
• Google currently indexes approximately 1 trillion Web pages
• It is estimated that the invisible web is 400‐550 times bigger and
contains 7,500 terabytes of information (as compared to 19
terabytes of information that Google currently indexes)
– http://aip.completeplanet.com/aip‐engines/help/help_deepwebfaqs.j
sp
• "The term ‘invisible web’ mainly refers to the vast repository of
information that search engines and directories don't have direct
access to, like databases."
– http://websearch.about.com/od/invisibleweb/a/invisible_web.htm

4. Examples
• Resides in a database or a table
• Created dynamically
• Accessible only to registered users
• Stored in subdirectories deep within a
website
• Generally no Flash, zip or executable files
• Exists in real time
• Social media‐‐‐can be hit or miss
• Excluded by the owner (robots.txt)

5. How Does it Differ From the Visible
Web?
"The ‘visible web’ is what you can find using
general web search engines"

6. Learn to Find “Invisible Documents”
• Include the word “database” as part of your
search
• Limit by filetype: PDF, .doc. xls, .ppt

7. Where do old web pages go? Learn to
locate them
Wayback Machine (www.archive.org)
Public.Resource.Org (http://public.resource.org)
CyberCemetery (http://govinfo.library.unt.edu/)
Google Instant Preview