Tools for Searching Information on the Web
•	Search Engines
•	Meta-searchers
•	Information Gateways
•	Subject Indexes
Search Engines	
•	Keyword searching tools
•	Most have huge databases of web resources gathered by robots, spiders or crawlers
•	Examples include: Lycos, Alta Vista, InfoSeek, Excite, etc.
Search Engines
•	Generally provide simple entry point 
•	Advanced search engines may provide many other options
•	Good for finding lots of information
•	Each search engine index documents differently
•	Searching for organisations, people, images
Meta-searchers
•	Simultaneous searching of a number of search engines
•	Sophisticated searching but relies on effective and speed of service
•	Examples:MetaCrawler, SavvySeach

Information Gateways
•	Subject related, reviewed  resources
•	Access to quality information
eg: The Official Guide to Geneva, as opposed to The Student’s Geneva Web Page.
•	Addressing more general information needs obtaining a general overview of what’s available for a particular subject area
•	Organising information more effectively
information sources are categorised according to their content
Example SOSIG - www.sosig.ac.uk

Subject Indexes 
Are Good For...
•	Addressing general information needs
obtaining a general overview of what’s available for a particular subject area
•	Organising information more effectively
information sources are categorised according to their content
Example: www.yahoo.com/

Classic Search Engine Problems
Overcoming Information Overload
Defining Your Topic, Scope and Keywords
Think about words which describe your topic effectively.  Be aware of..
–	Alternative spellings
–	Use of synonyms
–	Use of plurals
–	Broader or narrower terms
–	Capitalisation
What sorts of information do you need?
–	Web or usenet?
–	Very recent material?
–	English language?
–	National or International?
Structuring Your Search
•	Use of Boolean Operators  - AND, OR, NOT
–	Asia AND AWORC
–	Asia OR AWORC
•	Use of field and phrase searching
–	“Beijing Platform for Action”
–	title:”Asian Women’s Resource Exchange”
–	domain: kr
•	Use of truncation
–	comput*
Choosing A Search Engine
Factors to consider:
•	ease of use
•	comprehensive: scope, size and coverage
•	control over the search
•	flexibility in searching
•	valid assessment of relevance
•	informative presentation of results
Quality Considerations
Content:
•	who is the intended audience?
•	how reliable is the information?
•	how comprehensive is the information?
•	are there links to other quality documents?
•	are there many ‘dead’ links?
•	how up to date is the information?
Quality Considerations 
Source and Ownership:
•	who is the author or owner of the information?
•	what is their designation or authority?
•	is contact information available?
•	is there evidence of sponsorship on the web site?
•	is any bias evident?
•	is there a copyright statement or a disclaimer?
Quality Considerations 
Structure and Layout:
•	are graphics sensibly used?
•	is it easy to navigate around the site?
•	does the text follow basic rules of grammar, spelling etc.?
Other Tools for Searching Information in Computer Network
•	Directory Services
•	Intelligent Agents
•	Archies
Directory Services
•	online services (White Pages) that provide means of searching for people and computers
•	Examples: CSO, Finger, LDAP, Netfind, Whois, X.500
•	More information: 
http://www.nexor.com/public/directory.html
http://www.rs.internic/tools/whois.html
http://www.critical-angle.com/ldapworld/survey.html
http://www-leland.stanford.edu/group/networking/directory/x500ldapfaq.html
Intelligent Agents
•	softwares which carry out tasks on behalf of users
•	from automating routine search tasks, to adapting to user routines and preferences
•	can take initiative to provide user with information not specifically requested but likely to be of interest
•	examples: 
Autonomy Agentware: http://www.agentware.com/index.html
Bargain Finder: http://bf.cstar.ac.com/bf/
Firefly: http://www.agents-inc.com/
LiveAgent: http://www.agentsoft.com/kiveagen.htm
More Like This: http://www.morelikethis.com
Search’97: http://www.agents-inc.com
WebCompass: http://arachnid.quarterdeck.com/qdeck/products/wc20
Archies
•	one of earliest tools for searching specific items across hundreds of servers
•	gathers data from servers which houses archives, organizes it, maintains it and provides search interface for it
•	Archie servers cooperate to provide searchable index of Internet information, worldwide in scope
•	popular for indexing anonymous ftp archives
•	has gone commercial, marketed as database tool 
Summary
•	Plan your search before you start
•	Make use of search query languages
•	Be prepared to go back and refine your search if you don’t find what you need at first
•	Developing a good search strategy will save you time and frustration in the long run