Transcript Uusing the world wide web for accessing information

Uusing
the
world
wide
web
for
accessing
information
Structure of the Web
The information available on the World Wide
Web travels over a computer network called
the Internet. The Internet consists of connections
between a vast number of computers around
the world.
Compared to publishing a book or producing a television show, creating a Web
page is easy and inexpensive.
Many individuals who cannot reach large audiences through traditional media,
such as books, radio, or television, can communicate their ideas on the Web.
In addition to these individually-produced Web pages, many businesses and
organizations are finding the Web to be an excellent method of distributing
information to the public.
Information on the Web
The Web has no overriding organizational scheme or structure. Unlike most
electronic databases, there is generally no indexing by topic or subject.
Although most information on the Web is "free" (i.e., it can be accessed without
restrictions, passwords, fees, etc), some resources on the Web require subscriptions. For
example, some newspapers only allow free access to selected articles and require
registration and payment for the entire issue.
Also, remember that information on the Web is not screened or edited. Since
anyone can publish a Web page, the type and quality of material tends to vary!
Types of Web Sites
•There are many different types of Web sites.
•Some Web pages provide
•information or news
• attempt to influence public opinion
•sell products
•Entertainment
•Personal outlets
•Many Web pages may blur the line between entertainment, information, and
marketing/advertising.
Web domains
The following are several broad categories or domains of Web sites which can be
distinguished by the letters at the end of the Web address. (A Web address is also
known as a Uniform Resource Locator or URL). These letters are a clue as to what
type of Web site you are visiting.
DOMAIN
.edu = educational
institution
SAMPLE ADDRESS
SAMPLE WEB SITE
http://www.ucsb.edu
.gov= government site
http://www.senate.gov
.org = non-profit
organization or
association
http://.www.ncaa.org
.mil = United States Military
or Armed Forces
http://.www.af.mil
.com = business;
commercially-based site
http://www.cocacola.com
The World of Coca-Cola
Fee-Based or Subscription Web Sites
Not all information on the Web is available for free, some sites are restricted to paid
subscribers.
University/Organization subscriptions
Often, universities and other organizations, such as law firms and businesses, subscribe
to specialized databases on the Web. These databases can only be accessed by
members of a selected community. For example, most of the electronic databases
provided by the J. Paul Leonard Library at San Francisco State are only available to
the campus community. Access to UofD subscription services are available at oncampus computers.
Individual/Personal subscriptions
Subscriptions to fee-based Web resources, such as the Inter-Am database, are also
available to individuals.
Some newspapers and magazines provide the full-text of their issues on the Web to
subscribers who are willing to pay. The Wall Street Journal, for example, has a web
version that is available by subscription.
Commercial services, providing customized information to individuals, are also
available, for a fee. An example of one such service is Hoover's company profiles.
Search Engines
Search engines are used to search for resources on the Internet.
When selecting a search engine, be aware that each search engine varies by:
 the amount of the Internet being searched
 the type of sources being retrieved
There is no search engine that will search the entire Internet at once. The most
popular Web search engines may only cover up to 25% of all the content that is
available. Often, information about coverage can be found in a search engine's Help
or About Us sections.
There are many search engines available on the Web. Here is a sample list:
Alta Vista / Excite / HotBot / InfoSeek / Lycos
Magellan / WebCrawler / Google / Northern Light
Search Engine Tips
Always look for the
HELP button on the search engine you select. Useful search features and options
may be explained there.
Feature
Symbol
Example
Action
+
+intellectual
+property
+patents
Finds Web sites where the term after the +
appears in the results.
Exclude a
keyword
-
+intellectual
+property patents
Finds Web sites with intellectual and
property, but not patents.
Search for a
phrase
""
Search within
the title of a
Web site
title:
title:mortgage
Search within a
site domain
site:
cherry
site:www.pepsi.c
om
Search using
truncation
*
finan* planning
Finds Web sites with finance, finances,
financial, etc.
Use Boolean
operator AND
AND
montana AND
camping
Finds Web sites with both terms.
Use Boolean
operator OR
OR
montana OR camping
Finds Web sites with either term.
Use Boolean
operator NOT
NOT
montana NOT
camping
Finds Web sites with montana, but not
camping.
Include a
keyword
"four score and
seven years ago "
Finds Web sites which contain the exact
phrase.
Finds Web sites with mortgage in the title
tag.
Searches within the site www.pepsi.com for
the keyword cherry
Subject Directories
•Subject directories are lists of Web sites arranged by topic or broad subject area.
They are great starting points and are useful for general topic browsing.
•For example, Google and Yahoo offer Web directories with a comprehensive
compilation of subject categories.
Metasearch Tools
Metasearch tools use several search engines at the same time to search the Web. This
can be a time saver when doing extensive searches where you require the broadest
coverage.
A few sample metasearch tools are:
Interpreting Web Search Engine Results

Look to see if the following information is available:
 annotation - most search engines provide "annotations" with search
results. An annotation is usually an explanation but these annotations usually
just show the first few sentences of the Web page. They often, however, provide
a good indication about the content of the site.
 ranking- some search engines rank results by various criteria such as
relevance, comparing the information in the site against the information in the
search query.
 date- the results from search engines provide a date which may be useful for
evaluating the currency of a Web site. Be aware that the date could refer to
when the page was created or updated.
 domain- most search engines provide the URL of the retrieved sites. Check the
domain of the URL to determine whether the Web page is hosted on an
educational site (.edu), a government site (.gov), an association/organization
(.org) or a commercial site (.com)
Once you have linked to a retrieved site, check to see if any information is
provided about the producer/creator of the Web page. Often this type of
information is available through links such as, about this page, about us, about
this site, or a link to the site's home page.
Evaluating Information from the World Wide Web
Anyone can publish anything on the Web.
The information you find on the web may not be screened or checked for accuracy! It
is up to you to evaluate the quality of the material you find on the Web.
The following questions can help you judge the quality of a particular Web site:
Accuracy
How reliable and error free is the information?
What kind of documentation or references are provided?
Authority
Is the author or source identified?
What kind of qualifications does the author have?
Is a credible sponsoring institution cited?
Is there a link back to the sponsoring institution's home page?
Objectivity
Is the site designed to inform, persuade, or sell?
Is personal bias apparent?
Currency
How recently was the site created or updated?
(This kind of information can be located by checking the header, body, and footer
of a Web document.)
Summary
This presentation covered the following objectives:
understanding what the World Wide Web is and how it is
structured
understanding how the Web is organized (or not organized)
knowing what types of information can be found on the Web
being able to identify the major types of Web sites
understanding the difference between "free" and "fee" Web sites
understanding and being able to use a variety of Web searching
tools
being able to evaluate and interpret Web search results