Introduction With the arrival of the WWW came the widespread availability of online information Answers to your questions are somewhere on the web, but how do you locate them?
DIRECTORIES Method of finding and organizing web information Offers a hierarchical representation of hyperlinks to web pages and presentations broken down to topics and subtopics Review and classified by human editors
Directories : classification General Specialized
Also called web directory or subject directory
Top level provides a wide range of broad topics. E.g. Music / Entertainment.
Also called subject guides or gateway pages
Deals with a variety of topics. E.g. law, medicine.
Benefits Easy to use Need not know what you are looking for
Search Engines : introduction A computer program Submit a query describing the information you want to locate Searches its databases to try and match your query Collates and returns a list of URL’s which matches your query Permits you to revise and resubmit a query
Search engines : classification General Specialized
Also called vertical search engine or a topic search engine
Retrieves information from a database that contains information on a wide variety of topics
Provides in-depth information on specific topics that may be valuable
Exists for a multitude of topics
Not as easy to use as directories. WHY??
Metasearch Engines Does not have their own database of information Calls many search engines to do the actual work Advantage: You can access a number of different search engines with a single query Disadvantage: You will get a lot of results which will not be of interest to you. Therefore you will spend a lot of time evaluating the results and deciding which link to follow
Directories and search engines : Popular MetaSearch Engines Directories Search Engines
Boolean Queries : AND operator B A B A A B B A A A B B A A B B B A B A A B B A A B A B
Boolean Queries : OR operator B A B A A B B A A A B B A A B B B A B A A B B A A B A B
Search Strategies Determine which search engine Possesses a user-friendly interface Has a easy-to-understand, comprehensive documentation Is convenient to access; that is you do not have to wait several minutes before being able to submit a query Contains a large database Does a good job in assigning relevancy scores