Internet Resources Discovery (IRD)

The Invisible Web

T.Sharon-A.Frank2

Contents

• What is the Invisible Web?• How big is the Invisible Web?• Why is there an Invisible Web

(and what’s in it)? • Case study – patent search• How to find Invisible Web resources?

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What is the Invisible Web?• Called also “Deep Web” in contrast to the “Surface Web”,

which is the Visible Web.• The term “Invisible Web” relates to content of pages that are

available and accessible on the Web, but are not accessible and not indexed by the regular SEs, and includes mostly:– searchable databases– excluded pages

• These pages do not appear in the SEs search results.• Finding information on the Invisible Web is available using

direct access or using Specialized SEs.• The extent of the Invisible Web is larger than the Visible Web.

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How Big is the Invisible Web?

According to BrightPlanet study (2000):• Deep web (Invisible web) is 500 times larger.

– Number of search utilities:• 45,000 search engines on the surface web. • 200,000 searchable databases within the deep web.

– Number of documents:• 1 billion documents on the surface web. • 550 billion documents within deep web.

• Deep web quality is 1,000 times greater.

• 95% of deep web information is publicly available.

http://www.brightplanet.com/technology/deepweb.asp

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Visible vs. Invisible Web

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More Details (1)

• Public information on the deep Web is currently 400 to 550 times larger than the commonly defined World Wide Web.

• The deep Web contains 7,500 terabytes of information compared to 19 terabytes of information in the surface Web.

• The deep Web contains nearly 550 billion individual documents compared to the 1 billion of the surface Web.

• More than 200,000 deep Web sites presently exist.

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More Details (2)

• Sixty of the largest deep Web sites collectively contain about 750 terabytes of information - sufficient by themselves to exceed the size of the surface Web forty times.

• On average, deep Web sites receive 50% greater monthly traffic than surface sites and are more highly linked to than surface sites.

• However, the typical (median) deep Web site is not well known to the Internet-searching public.

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More Details (3)

• The deep Web is the largest growing category of new information on the Internet.

• Deep Web sites tend to be narrower, with deeper content, than conventional surface sites.

• More than half of the deep Web content resides in topic-specific databases.

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More Details (4)

• Total quality content of the deep Web is 1,000 to 2,000 times greater than that of the surface Web.

• Deep Web content is highly relevant to every information need, market, and domain.

• A full ninety-five per cent of the deep Web is publicly accessible information -- not subject to fees or subscriptions.

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Invisible Web?!

The Invisible Web

google

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Is it Really that Big?

• Some argue that the Invisible Web is actually only 50-80 times bigger than the Invisible Web.

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Deep Web Growing Faster than Surface Web

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Original deep content exceeds all printed global content

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The Size Today???

• 2000 - 1:550 (with source)

• 2004 - 10:1000 (estimate) - 2 orders of magnitude more

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Why is there an Invisible Web? (1)

1. Specialized searchable databases:– Have dynamic pages.– Require parameters and user judgment.– Require user and password.

2. Script-based pages:– Include “?” in their URL.– Hazard to SEs – traps.

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Why is there an Invisible Web? (2)

3. Real-time, constantly changing, content.

4. Very large websites are partially indexed.

5. Private/secret websites:– Internal companies portals.

– Excluded from SEs (using robots.txt or similar schemes).

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Why is there an Invisible Web? (3)

6. Multimedia (and other formats) files– Special formats

– Examples: PDF, DOC, PPT, GIF, Flash

– Some of the SEs can’t, or won’t index these.

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Why is there an Invisible Web? (4)

7. Additional reasons (mostly spam related or resources saving):– File size– Number of words in the page– Pages requiring cookies– Other spam characteristics– Multimedia files– Files and URLs with special

characters.

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8. Non-linked pages (no incoming/inbound links).9. Pages on servers with dynamic IP.

• For example, 5% of the Internet is not connected!The Internet is partitioned and there exists “Dark Address Space”, or prefixes that are not reachable for one provider but that are available from other providers for long periods of time.

5% of the total number of prefixes in the Internet or tens of millions of end hosts.

Source: Arbor Networks -http://www.arbornetworks.com/downloads/research38/dark_address_space.pdf

Why is there an Invisible Web? (5)

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Invisible

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The Invisible Web is mostly topic databases

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Databases (1)

• Tens of thousands of databases in different topics exist.

• The SEs know many databases, but not their content.

• Entry to many databases is blocked, the SE knows its URL (main page), but not the information inside!

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Databases (2)

• Searching these databases requires entry via the site user interfaces, and often also registration/password/cookies.

• The advantage of using the database’s user interface is that it is specialized and designed to get the best results searching that specific information.

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Specialized interface

VS.

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Topics of databases (1)

• Auction• Public, government

information• Expert directories• Buyer’s guides• Scientific databases

from educational institutions and research labs

• News & magazine archives

• Discussions• Mailing list archives• Product reviews• Legal databases• Shopping catalogs• Medical databases

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Topics of databases (2)

• Product support knowledge bases

• Phone numbers, address, and email databases

• and much more

• Dictionaries

• Thesauri

• Patent databases

• Trademark databases

• Genealogy and surname lists

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Sites by Subject Area

0.00% 5.00% 10.00% 15.00%

Health

Government

Engineering

Employment

Education

Computing/Web

Business

Arts

Agriculture

Series1

0.00% 5.00% 10.00% 15.00%

Travel

Shopping

Science, Math

References

Recreation, Sports

People, Companies

News, Media

Lifestyles

Law/Politics

Humanities

Series1

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Example Databases (1)

• WebDietitian– http://www.webdietitian.com

• AnimalSearch – http://animalsearch.net– A database for family-safe animal-related sites.

• NatureServe Explorer– http://www.natureserve.org/explorer– Online encyclopedia, provides authoritative

conservation information on plants, animals, & ecological communities.

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Example Databases (2)

• Search Systems– Public systems: courts, criminal records, birth, death,

marriages, recalls, etc.– http://www.searchsystems.net/

• PubMed– Provides access to 14 million + MEDLINE citations– http://www.ncbi.nlm.nih.gov/entrez/query.fcgi

• MedlinePlus– Trusted Medical Information– http://www.medlineplus.gov/

• National Library of Medicine– Directory of trusted medical information – http://www.nlm.nih.gov

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Advantages of such databases• Quality of Content (Authority)• Deep Content on Subject Area (Comprehensiveness) • Focused Databases (Limited Scope) Smaller Universe

of Documents to Search (Maximize Precision/Recall) • Material Unavailable Elsewhere on the Web

(Uniqueness)• Many Options to Limit, Sort, Interact with the Data

(Maximize Precision)• Timeliness vs. Time Lag of General Search Tools

(Currency)

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Will the Invisible Web become Visible?

Definitely!

• Using intelligent SEs.

• After a while, new information is being updated in SEs that can access the invisible web, and make it visible.

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Google and the Invisible Web

• Google’s Search “By Number” Service, examples:– UPS tracking numbers: "1Z9999W99999999999"

– FedEx tracking numbers: "999999999999"

– USPS tracking numbers: "9999 9999 9999 9999 9999 99"

– Vehicle ID (VIN) numbers: "AAAAA999A9AA99999"

– UPC codes example: "073333531084"

– Telephone area codes: "650"

– Patent numbers: "patent 5123123" (Need to put the word "patent" before your patent number).

– Google Scholar

• http://www.google.com/help/features.html#number

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Yahoo Shortcuts• Yahoo provides a lot of “shortcuts” to retrieve

information:– Gas prices– Exchange rates– Hotels– Airport Information– Sports Scores– Stock Quotes– and many more

• http://help.yahoo.com/help/us/ysearch/tips/tips-01.html

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Case Study - Patents

• Searching for “CD box” in patent abstract.

• Google’s Search by Number

• USPTO

• FreePatentsOnline

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Google’s Search by Number

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USPTO Database

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USPTO Advanced Search

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Free Patents Online

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Free Patents Online (Continuation)

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Searching Database “CD box”

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Searching Google

Example: Irrelevant50 results – mostly irrelevant

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Is the Invisible Web Invisible ?

GoogleYahoo!

Google

X

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How to Find Invisible Web Resources?

Search for sources – not information!

• Two-step searching in general search engines.

• Specialty Search Engines

• Subject Directories

• Digital Libraries

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Two-Step Searching

• Use general search engine (such as Google) to search for a good database, then search for the information inside that database/website search engine.

• Examples words to add in the query:– database– association– tutorial– demographics– “how to”– webcam– streaming video + search engine– encyclopedia– product review

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Invisible Web Pathfinders• Sherman-Price Invisible-Web Directory

http://www.invisible-web.net/

• CompletePlanet http://www.completeplanet.com

• Beaucoup http://www.beaucoup.com

• Turbo10 http://turbo10.com/

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Sherman-Price Invisible-Web directory

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Invisible-Web directoryPeople Search

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Complete Planet

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Beaucoup (1)

• Over 2500 engines

• The engines listed on the main site are "free information" sites -- a *lot* of information.

• Subject Directory/Annotated

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Beaucoup (2)

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Turbo10 (1)

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Turbo10 (2)

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Turbo10 (3)

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Turbo10 – Edit Collections

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More Invisible Web Pathfinders

• Librarianas’ Index to the Internet http://www.lii.org

• MeL Michigan eLibrary http://www.mel.org/

• Internet Scout Project http://scout.wisc.edu/

• Infomine http://infomine.ucr.edu/

• More: http://www.calvin.edu/library/searreso/internet/webdirec.stm

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References• http://websearch.about.com/od/invisibleweb/• http://www.shelton.cc.al.us/library/lbs102/

lbs102session12.html• http://www.lib.berkeley.edu/TeachingLib/Guides/

Internet/InvisibleWeb.html• http://www.campus-technology.com/article.asp?

id=7477• http://www.searchengineoptimising.com/optimisation• http://www.press.umich.edu/jep/07-01/bergman.html