1. Web searching & the invisible web
Finding things that are hard to find
© Tefko Saracevic

2. Dictionary definitions
World wide web :
Internet-connected files
the very large set of linked documents and other files located on computers connected through the Internet and used to access, manipulate, and download data and programs
Invisible - dictionary definition:
not easily noticed; not noticed or detected readily
Invisible web – not yet in the dictionary
© Tefko Saracevic

3. What is “Invisible web?”
Materials that general search engines cannot or WILL not include in their collection of web pages (indexes)
You cannot find through general search engines
Contains a vast amount of information resources
much of it authoritative & higher quality than visible web
quality becomes a main issue
much of it specialized
a lot of it also fluid or streaming or real time
“You can’t step in the same river twice”
much of it free
Many times larger than the visible Web
© Tefko Saracevic

4. in other words… There is much more to the web than or
Distribution of use:
© Tefko Saracevic

5. Why search engines do not cover all?
Size: web is huge, cannot cover all
Economics: associated costs are high
engines support themselves mostly by ads
also a number of engines have rank per pay & crawl update per pay - providing paid listings first & mostly
Technical: still a challenge & limited capabilities
also some file formats hard to cover
Spam: eliminating bad also looses good
Restrictions: some site do not let in
Deep structure: some sites complex
© Tefko Saracevic

6. How do search engines work? Main parts
Crawlers, spiders: go out to find content
looking for new & changed sites
periodic, not for each query
no search engine works in real time
Organizing content: labeling, arranging
indexing for searching or classifying as directory
Databases, caches: storing content
Retrieval engine: searching on basis of query
Interface: handles query, displays results
All based on various, mostly proprietary algorithms
© Tefko Saracevic

7. Search engine coverage
No engine covers more than a fraction of WWW
estimates: none more than 16%
Hard (impossible) to discern & compare coverage
Many national search engines
own coverage, orientation, governance
Many topical or domain search engines
own coverage geared to subject of interest
Many comprehensive sources independent of search engines
some compilations of evaluated web sources
© Tefko Saracevic

8. Search engines differ
Substantial differences among search engines on each of these parts
Need to know how they work & differ
Information about search engines:
Search Engine Watch
ratings, news, statistics, charts, explanations, tutorials
Search Engine Showdown
“The users’ guide to web searching” - run by a librarian, news links, ratings
© Tefko Saracevic

9. Invisible web searching: Basic approach
The first step in determining the best approach for searching the invisible web is to have a clear idea of what you’re seeking
extensive user modeling
Limit your search to appropriate resources & tools for the particular type of information you’re looking for
know your sources
know how to find appropriate sources
shades of “Knowledge is of two kinds…”
© Tefko Saracevic

10. Specialized sources - particularly for the invisible web
The rest of the lecture covers:
Meta search engines
Specialized engines & catalogs
Domain (subject) engines & catalogs
Reference sources
Libraries as web sources
Virtual libraries
Subject databases
Societies, organizations
Good old books
© Tefko Saracevic

11. Meta search engines Meta search engines search multiple engines
© Tefko Saracevic
Meta search engines
Meta search engines search multiple engines
getting combined results from a variety of engines
Finding a search engine or meta engine:
SearchEngines.com
search for engines by topic, geography, reference
Search Engine Guide
engines categorized by topic; other engine information
Search Engine Colossus
international directory of search engines by country, topic from 198 countries and 61 territories; engines in choice of languages
© Tefko Saracevic
Priciples of Searching

12. Sample of meta engines Some meta engines provide organized results:
Dogpile
results from a number of leading search engines; gives source, so overlap can be compared; (has also a (bad) joke of the day)
Surfwax
gives statistics and text sources & linking to sources; for some terms gives related terms to focus
Teoma
results with suggestions for narrowing; links resources derived; originated at Rutgers
Turbo10
provides results in clusters; engines searched can be edited
© Tefko Saracevic

13. meta search engines (cont.)
Large directory
Complete Planet
directory of over 70,000 databases & specialty engines
Results with graphical displays
Vivisimo
clusters results; innovative
Webbrain
results in tree structure – fun to use
Kartoo
results in display by topics of query
© Tefko Saracevic

14. Domain engines & catalogs
Cover general & specific subjects
Open Directory Project
large edited catalog of the web – global, run by volunteers
BUBL LINK
selected Internet resources covering all academic subject areas; organized by Dewey Decimal System – from UK
Profusion
search in categories for resources & search engines
Resource Discovery Network – UK
“UK's free national gateway to Internet resources for the learning, teaching and research community”
© Tefko Saracevic

15. domain engines … Available in variety of domains & subjects – rich!
Think Quest – Oracle Education Foundation
education resources, programs; web sites created by students
All Music Guide
resource about musicians, albums, and songs
Internet Movie Database
treasure trove of American and British movies
Genealogy links and surname search engines
well.. that is getting really specialized (and popular)
© Tefko Saracevic

16. domain engines … Scholarship, science
Psychcrawler - Amer Psychological Association
web index for psychology
Entrez PubMed – Nat Library of Medicine
biomedical literature from MEDLINE & health journals
CiteSeer - NEC Research Center
scientific literature, citations index; strong in computer science
Scholar Google
searches for scholarly articles & resources
Infomine
scholarly internet research collections
© Tefko Saracevic

17. Reference services Reference services - several models Ask Jeeves!
Q&A, directories, answers etc.
Ask Jeeves!
most popular, commercial
Information Please
almanac type questions
RefDesk
access to a number of reference tools
Wikipedia
web encyclopedia in many languages
© Tefko Saracevic

18. reference … Digital reference - new service area for libraries
QuestionPoint L of Congress & OCLC
project for a global reference network
Virtual Reference Desk – L of Congress
large compilation of web reference sites
LiveRef - maintained at Iowa State U
a registry of real time digital reference services
© Tefko Saracevic

19. Libraries as web sources
Academic, national libraries providing open collections & services; models vary
Rutgers libraries - big long term effort
University of California, Berkeley
a most elaborate effort together with Sun Corporation
LibWeb U California, Berkeley
“lists currently over 7200pages from libraries in over countries”
Bibliothèque Nationale de France
includes virtual exhibitions, among others
© Tefko Saracevic

20. Virtual libraries on the Web
Libraries emerging only on the Web
Virtual Library –
Switzerland, US, UK & other countries – ‘oldest virtual library on the Web’
Internet Public Library U of Michigan
also a long term effort
Librarians Index of the Internet
very popular and comprehensive
Digital librarian
“a librarian's choice of the best of the Web “ – compiled and annotated by a librarian
© Tefko Saracevic

21. virtual libraries … Academic Info Digital Library Gabriel
many links to digital collections & resources in various subjects
Gabriel
Gateway to European National Libraries
Museum of online museums
a delight
Stanford Encyclopedia of Philosophy
a comprehensive encyclopedia and library
The historical New York Times Project
universal library – ongoing digitization
© Tefko Saracevic

22. Subjects resources Many subject specific sites
rich & often unique coverage & services
different approaches & requirements
Examples in health related domains:
WebMDHealth
news, medical information
Rxlist
The Internet Drug Index
Mayo Clinic HealthOasis
health advice
Kidshealth
sites for parents, kids, teens
© Tefko Saracevic

23. Subject resources … Scholarship, humanities, government
KIRKE - Katalog der Internetressourcen für die Klassische Philologie aus Erlangen
German; a variety of resources for classics
Perseus Digital Library Tufts University
covers antiquity to renaissance; one of the best subject sites on the web; affected the whole field
Sch of Slavonic & East European Studies, University College London
includes country resources, e.g. Croatia
U Mich Document Center
official documents from all over the world
© Tefko Saracevic

24. Subject resources … Growing number of resources in arts, museums
MuseumStuff.com
“We have 1000's of museums, zoos, historical societies and related organizations in our database”
The State Hermitage Museum
One of the greatest museums in the world, and one of the best museum site – developed with IBM help
National Museum of Science and Technology Leonardo da Vinci
Guess where those pictures came from. A delight!
© Tefko Saracevic

25. subject resources … Diotima Moving Images Collections And, of course …
Materials for study of women and gender in the Ancient World
Moving Images Collections
“MIC documents moving image collections around the world.” Part particularly oriented toward science educators. Now at Library of Congress, but developed at Rutgers.
And, of course …
Snoopy
The Official Peanuts Website
© Tefko Saracevic

26. Societies, organizations
Many societies, agencies developed their sites
great many rich sources for searching & resources
differences in requirements, depth, richness
Assoc. for Computing Machinery
Digital Library; subscription or registration or through RUL
US State Department
about the U.S & other countries
FirstGov
the US government official web portal
Ocean Planet NASA
presentation of earth & its vast oceans
ArXiv Cornell U, National Science Foundation
e-print service in the fields of physics, mathematics, non-linear science, computer science, and quantitative biology
© Tefko Saracevic

27. Archiving, books on the web
Internet Archive – a large undertaking
includes web archive & lots more publicly available & free
10 billion web pages archived from 1996 to a few months ago
Wayback Machine – search to look at old versions of web pages
Books on the web
Million Book Project
digitizing books and providing free access
International Children’s Digital Library
online children books
Digital books Index
“links to more than 105,000 title records from more than 1800 commercial and non-commercial publishers, universities, and various private sites”
© Tefko Saracevic

28. Language barriers on the Web
English still the major language
but declining, now slightly over 50%
Multilingual retrieval search engines
Euroseek
searches in a number of languages
All the Web
results in 45 languages
© Tefko Saracevic

29. Web news; keeping up
What is going on on the Web? Some major sources of news and evaluations:
Free Pint
newsletter, articles, links; nice & sometimes quirky
Internet Resources Newsletter
UK based; monthly newsletter for “academics, students, engineers, scientists and social scientists”
ResearchBuzz
daily updates; many aspects; “Collection of items on search engines, online databases, and other information resources”
About.com Web Search
tools, Web Search Forum
© Tefko Saracevic

30. keeping up … Keeping up through blogosphere: Information Today
trade & professional monthly newspaper & web site; industry news; searcher columns; general analyses of trends
Keeping up through blogosphere:
Resource Shelf
bloger about internet (and some other stuff) with archive; it has really good and really bad exchanges & threads
New York Times blogrunner - The annotated NYT
blog tracking of NYT articles, topics, authors; thread into discussion of many other weblogs; includes net & web topics
© Tefko Saracevic

31. Finding links & listings – back to good old books with a new twist
Number of books on web searching have also sites with links in the book, updates, news
Extreme Searcher Randolph Hock
update of a popular book; links by chapter topics
The web library Nicholas G. Tomaiuolo
spotlights free resources, links by chapter and new topics –done by a librarian
The invisible web Chris Sherman & Gary Price
original book on the topic, links organized by subject
p.s. most, but not all, of the sites in this lecture can be found on those sites – and much, much more
© Tefko Saracevic

32. Evaluations, ratings
Evaluating web sites: a prime responsibility of searchers & all information professionals
Many sources evaluate web sites:
The Scout Report –
librarians’ BIBLE! Annotations. Comprehensive.
Medical Library Association
ten most useful sites for consumer health
MLA user guide
for finding & evaluating health information on the web
Web 100
commercial, user ranking & evaluation of web sites
Evaluating web pages UC Berkeley
tutorial and guide
© Tefko Saracevic

33. Needed for Web searching
Knowledge & competencies on
variety of web sources & their organization
search engines
web search strategies
search dynamics, feedback
Keeping up & up & up
Why? many reasons, such as:
constant updates, changes, innovations
many domain/subject specific
fluidity very high
© Tefko Saracevic

34. Needed for web searching by professionals
Knowledge of SOURCES in area of interest
search engines not enough
not too helpful in finding these other sources; structure hard to discern
find & use specialized sources
Evaluation of sources
a key professional skill!
application of standard criteria & web criteria:
authority; accuracy; currency (timeliness);
objectivity; coverage, persistence, usability
© Tefko Saracevic

35. Needed competencies … Knowledge of users & use Knowledge of searching
Use of technology
Adaptability, flexibility
Integration with other resources
Teaching others
Constant learning & update
again: keeping up, keeping up, keeping up
and again: keeping up, keeping up, keeping up
© Tefko Saracevic

36. But now really: How to do it?
information
WWW
© Tefko Saracevic

37. Web is still a mystery!
© Tefko Saracevic

38. thank you hvala ďakujem vám danke merci grazie gracias
© Tefko Saracevic

39. Images from the invisible web
© Tefko Saracevic

40. images …
© Tefko Saracevic

41. images …
© Tefko Saracevic

42. and of course…
© Tefko Saracevic

43. P.S. a nice site Poem by Emily Dickenson: In a library
Who will write a poem:
In a digital library?
© Tefko Saracevic

44. P.S. a few weird sites… SelectSmart.com James Dean official web site
all kinds of quizzes for you
James Dean official web site
Deaducated
Dead Librarians’ Society
Livejournal
blogs & authoring tools; and many pathetic entries
© Tefko Saracevic

45. Sources About.com Web Search http://websearch.about.com
Academic Info Digital Library
All the Web
Ask Jeeves!
Assoc. for Computing Machinery
Bibliothèque Nationale de France
BUBL LINK
CDNET Search.com
CiteSeer
CompletePlanet
Deaducated
Digital book index
Digital librarian
Diotima
Dogpile
Entrez PubMed
Extreme Searcher
Free Pint
Gabriel
Genealogy
© Tefko Saracevic

46. sources … Hermitage http://www.hermitagemuseum.org/html_En/index.html
© Tefko Saracevic
sources …
Hermitage
Information Please
International Children’s Digital Library
Internet Archive
Internet Public Library, Michigan
Internet Resources Newsletter.
James Dean
Kartoo
KIRKE
Leonardo da Vinci Museum
Librarians Index to the Internet
Live Journal
LiveRef
Mayo Clinic
Medical Library Assoc. ten top sites
Medical Library Assoc. user guide for health inf.
Medscape
© Tefko Saracevic
Priciples of Searching

47. sources …
Million Book Project
Museum of online museums.
MuseumStuff
NYT blogrunner
NYT historical project
OCLC Web Characterization Project
Open Directory Project
Perseus Digital Library
Profusion
Psychcrawler
QuestionPoint
ResearchBuzz.
Resource Shelf
Rutgers Libraries
RxList
Sch of East Eur & Slavonic Studies
Search Engine Colossus
Search Engine Guide
Search Engine Showdown
© Tefko Saracevic

48. sources … Search Engine Watch http://searchenginewatch.com/
Select Smart.com
Snoopy
Stanford Encyclopedia of Philosophy
Surfwax
Teoma
The invisible Web
The Scout Report.
The Web Library
Think Quest
Turbo10
U California Berkeley
U Mich Documents Center
US State department
Virtual Library
Virtual Reference Desk
Vivisimo
Web 100
Webbrain
WebMD
Wikipedia
© Tefko Saracevic