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1. IST 497 E Meta-Search, Pradeep Teregowda
IST 497E Information Retrieval
and Organization
Meta Search

2. Overview
What is a Meta Search Engine
Features
Differences
Architecture
Some Meta Search Engines
Conclusions and Future ?

4. Overview
What is a Meta Search Engine ?
What is a Meta Search Engine ?
Traveling Further
Why Meta Search ?

5. What Is a Meta Search Engine ?
Dictionary meaning for Meta:
“more comprehensive : transcending.”-
webster.com
Simple Explanation
“A Meta Search engine allows you to search
multiple search engines at once, returning
more comprehensive and relevant results,
fast.” –MetaCrawler {modified}

6. Traveling Further
A little bit of History:
 Started with Harvest (1995) –[Ref:
Information Discovery and Access System
– C. Mic Bowman et al].
 Was developed for gathering information from
repositories, building topic-specific content
indexes, web-caching,flexible searching.
 In many ways current Meta Search
engines have similar aims.

7. Why Are Meta Search Engines
Useful ?
Meta Search improves the Search
Quality in many ways:
 Comprehensive,
 Efficient,
 One query queries all {one-click paradigm},

8. Why Meta Search ?
Individual Search engines don’t cover all the
web by themselves,
Individual Search Engines are prone to
spamming {people trying to raise their ranking
profile. In a non-legitimate manner or to
promote commerce},
Difficulty in deciding and obtaining results
with combined searches on different search
engines,

9. Why Meta Search ?
Data Fusion {multiple formats
supported},
In Case of niche search engines
provides the ‘big picture’,
Takes less effort.

10. Overview
Features
Features

11. Features.
Unifies the Search Interface and provides a
consistent user interface,
Standardizes the query structure,
May make use of an independent ranking
method for the results {rank-merging},
May have an independent ranking system for
each search engine/database it searches,
Meta Search is not a search for Meta Data.

12. Overview
Differences
Differences {Search vs. Meta Search}.

13. Differences {Search Vs. Meta-
search}
Doesn’t generally have a Database by itself,
Does not search{crawl} the web.
 A Meta-Search Engine in terms of search
engine.
 Essentially is a hub of search engines/databases
accessible by a common interface providing the user
with results which may/may not be ranked
independently of the original search engine/source
ranking.

14. Overview
Architecture/Internals
A block representation,
What do those blocks do ?,
Queries,
Ranking.

15. Architecture
S E 1 S E 2 S E 3
Dispatcher
Display
User
Interface
Knowledge
Personalize
Query
Feedback
User
Web

16. What Do Those Blocks Do ?
User Interface
 Normally resemble search engine interfaces with
options for
 Types of search [Media]
 Search Engines to Use
Dispatcher
 Generates actual queries to the search engines by
using the user query
 May involve choosing/expanding search engines
to use

17. What Do Those Blocks Do ?
Display.
 Generates Results page from the replies received,
May involve ranking,parsing,clustering of the
search results or just plain stitching.
Personalization/Knowledge.
 May contain either or both. Personalization may
involve weighting of search results/query/engine
for each user.

18. Queries
STARTS { protocol }.
 A simple protocol that text search engines should follow
to facilitate searching and indexing multiple collections of
text documents.
 Choosing best source for a query,
 Evaluating a query at those sources,
 Merging the query results from them.
Inquirus: Expand Queries.
Ex: (What does Satellite stand for = Satellite stands
for).

19. Independent Ranking
Stitch together the results [Dogpile],
Selection of a particular Search Engine based
on a query – a meta index [SavySearch-
Resource Balancing],
Rank merging based on Search Engine rating
[MetaCrawler],
Context analysis for search results with
respect to the query [Inquirus].

20. Fusion of Other Media
Inquirus.
 Motivation for a meta-search {Images}:
 Queries from the user can be modified, since individual
search engines are good at different types of queries the
results are very good.
 How ?
 See Reference {Skipped because of topic overlap}.
 Can it work for others ?
 Example: FTP,Music – Probably yes [P2P searches].

21. Other Work
Other work {Media Fusion}.
 MetaSEEk.
 Visual Search Engine [for images],
 Makes use of query by example.
 Ixquick.
 MP3,Images,News.[all come from different
search interfaces –may not exactly be fusion].
 Dogpile.
 Multimedia,Images,News,Files.

23. Overview
Some Meta Search Engines
On the web,
Why are they not so popular ?,
Some Reviews.

24. Meta search Engines on the Web
MetaCrawler,
Ixquick,
Inquirus,
SavySearch {now cnet search ?},
Dogpile,
Sherlockhound,
Vivisimo.

25. Why Are They Not So Popular ?
Ads !
 Some Meta Search engines pick up ads as part of
search results from the participating search
engines.
 Example: Dogpile.
 Similar reasons as general search engines (ads
clutter search results).
 Example: MetaCrawler,Ixquick.
Paid Placement Search Engines included,
Relation with the search engines they depend
on. {load,interaction}….

26. Why Are They Not So Popular ?
Results as good as the worst search
engine in the group.
 Combining results using meta-index and
rankings can lead to incorrectly ranked
results from a search engine reducing the
relevance of correct results.
 If your highly ranked search engine returns
a badly ranked result, then your results are
also badly ranked.

27. Some Reviews
Search Engine Watch [May 2001]
Meta Search Engine % Results From A
Major Search Engine
Vivisimo 100 % [No Ads]
Ixquick 70 %
MetaCrawler 48 %
Dogpile 14%

28. Overview
Conclusions and Future
Conclusions and Future

29. Conclusions and Future
Vivisimo reported 43 % increase in
traffic –[wired.com Aug. 14, 2001],
Apple ‘Sherlock’ has been popular,
Multiple Media Search,
P2P Searches ?,
Growth or Niche Search Engines.

30. References
The MetaCrawler Architecture for Resource
Aggregation on the web(1997) – Erik Selberg
& Oren Etzioni.
Context and Page Analysis for Improved Web
Search(1998) –Steve Lawrence & C. Lee
Giles.
Experiences with Selecting Search Engines
Using Metasearch(1997) – Daniel Dreilinger
& Adele E. Howe.

31. Time to Wake Up…

33. Web References
Search Engine Watch Article [Meta
Search Or Meta Ads?],
Wired Article [Searching For Google’s
Successor],
MetaSEEk [Writeup],
Text and Image Meta Search on the
Web [Citeseer Paper Reference].