THE DEEP WEB

1
THE DEEP WEB

• A Brief Introduction

Soleil Surette December 5, 2006
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Deep Web aka Hidden Web aka Invisible Web

• Objectives
• What is it?
• How does it work?
• Is it useful?
• How to find it?

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What is the Deep Web?

• The Deep Web is the part of the Internet that is
  not indexed by most search engines
• In January 2006, it was estimated that search
  engines accessed 8 BILLION pages of information.
• At the same time approximately 900 BILLION pages
  are inaccessible or difficult to access for these
  search engines

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3 kinds of Deep Web resources

• Online databases
• Sites that require a password or registration
• Sites whose owners have blocked search engines
  from gathering information

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How search engines work (Briefly)

• Use web crawlers (computer programs) to find
  unknown websites and webpages.
• Follow all the links to other pages until nothing
  left to follow
• Return to search engine with that information
• Search engine indexes it

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How the Deep Web works

• It is information that the web crawlers cannot
  access
• Databases for example

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Why do search engines have trouble?

• They dont think
• Web crawlers cannot produce questions to ask
  databases
• They cannot fill out registration forms or chose
  passwords
• They cannot negotiate with blocked sites to be
  let in

8
But is the Deep Web useful?

• Yes, because
• Information you will find is more specific
• Better quality
• With a bit of leg work you will be able to find
  relevant information faster

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How can you find this hidden information?

• Library websites Librarians Internet Index
  www.lii.org
• Specialized search engines www.completeplanet.com
  
• Use the term database when using a search
  engine plane crash database www.google.ca

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Exercise

• In groups of 2 please use the Librarians
  Internet Index (www.lii.org) to find
• Two deep web resources on hiking
• A deep web resource for news information that is
  specifically for journalists
• Please write down your results, how you found
  them, and why you think they are part of the Deep
  Web.

11
Review

• What is the Deep Web?
• How does it work?
• Is the Deep Web useful?
• How can Deep Web resources be found?

12
Thank-You

• Questions? Comments? Want to learn more?
• Please contact me at ssurette_at_ualberta.ca