1. The Invisible/Deep
Web
Holly Yu
March 2001

2. What is the Invisible/Deep
Web?
The Invisible Web consists of searchable
information resources whose contents cannot
be indexed by traditional search engines.
Include:
---Records in databases
---Certain file formats: PDF, Flash, Streaming
media
---Most real-time data: stock quotes, weather

3. The Visible vs. the
Invisible/Deep Web
The visible web pages present their content in
static HTML or ASP and are capable of being
fully indexed by spiders or crawlers that follow
links on static web pages.
The invisible web is made up of searchable
databases with results in answer only to a
direct query.
Resources in the invisible web is often much
higher quality than the visible web.

4. Facts: The Visible and
Invisible/Deep Web
The Invisible/Deep Web contains:
--550 billion individual documents
--7,500 terabytes of information
--1,000 to 2,000 times greater than that of
the visible web
--95% of the deep web is publicly accessible
information
The Visible Web Contains:
--1 billion individual documents indexed by
search engines
--19 terabytes of information

5. Challenges
Lack of knowledge. I did not know the
invisible web existed!
A learning curve. There are numerous
resources to consider.
Resources coming and going. Staying
current!
Knowing where to begin searching.

6. Approaches
The Direct Approach
Provides access to the search interfaces of resources that
are not easily searchable from the major search engines.
Examples: Direct Search
Complete Planet
A Single Portal Search Form
Submits a user to user-designated sources for
simultaneous processing
Example: All Seeing Eye
Multiple & Integrated Search Forms
Simultaneous, parallel processing with results for viewing,
rather than manipulating multiple browser windows
Example: CiteLine Professional

7. Approaches
The Direct Approach
Provides access to the search interfaces of resources that
are not easily searchable from the major search engines.
Examples: Direct Search
Complete Planet
A Single Portal Search Form
Submits a user to user-designated sources for
simultaneous processing
Example: All Seeing Eye
Multiple & Integrated Search Forms
Simultaneous, parallel processing with results for viewing,
rather than manipulating multiple browser windows
Example: CiteLine Professional