Searching the Web
What is search engine?
XP• A web-based program that allows users to submit query to an online database.
• Example
– Altavista.com – AskJeeves.com – Excite.com – Google.com – HotBot.com – Infoseek.com – Lycos.com
How to use search engine?
XP• Using keywords
– Use “” around phrases which are less than 3 characters
– Combine all keywords separated by spaces
Advanced Search Features
XP• Purpose: helps user to refine their search
• Features including
– File type
– Boolean operators – File creation date
– Terms occur in a page
– Search for a particular domain
How web pages are found?
XP• Knowbots /robots/bots/spiders/crawlers
– Computer program that crawl from one page to another using links
• Site notification
– Web site owner place their URL in the search engine’s database
– Using web site registration services
– Pay a fee
Pros and Cons of search engine
XP• Pros
– It searches large database for your keywords
• Cons
– Too many unrelated results
Directory Outline
XP• Contains a list of topics that can be browsed and searched ranging from general to specific
• Example: yahoo.com, about.com
• Pros
– The sites are categorized properly
• Cons
– Do not use knowbots for data retrieval/indexing – Indexed by human
– Small volume of indexed pages
Bibliography Database
XP• Online collection of research materials such as journals and book
• Assembled by professionals
• Indexed according to keywords
• Have abstracts or even complete text of the article
• User need to pay fee to access them
• Example: http://www.ebscohost.com/
• Pros
– High quality and reliable (reviewed and edited by experts)
• Cons
– Out of date (rely on human effort)
Site specific search engine
XP• Search only the data on a single website
• Site map can be used as a navigational guide
• Example: http://www.youtube.com/
• Pros
– Results are very specific without unrelated results
• Cons
– Only search the site they are attached to, so they are far more limited than general search engine
Subject specific search engine
XP• Seek out the data stored on many different web sites about a particular topic (eg parenting, gardening, entertainment etc)
• Example: www.imoutdoors.com (about outdoor activities)
• Pros
– Search for a specific type of data
• Cons
– Not comprehensive
Metasearch engine
XP• Search engine that submit a key term to several search engines simultaneously.
• Not a search engine, only an interface to many other search engines.
• Example
– Dogpile.com
Metasearch engine
XP• Pros
– Search several search engines at once – Effective for simple searches
• Cons
– Some metasearch engines don’t adapt the search request for specific search engines.
– Can’t possibly go deep enough into each database to get accurate results
– The technology is outdated. Major developments are done on search engine first
Expert inquiry
XP• User ask something using search engine and the answers are given by expert in certain field.
• Example
• http://inventors.about.com/library/blexpert.htm?once=true&
