Searching the Web

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Searching the Web
Tutorial 4

• Using Search Engines and
• Directories Effectively

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Objectives

• Determine whether a research question is specific
  or exploratory.
• Learn how to formulate an effective Web search
  strategy to answer research questions.
• Learn how to use Web search engines, Web
  directories, and Web meta-search engines
  effectively.

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Objectives

• Use Boolean logic and filtering techniques to
  improve your Web searches.
• Use advanced search options in Web search
  engines.
• Assess the validity and quality of Web research
  resources.
• Learn about the future of Web search tools.

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Types of Search Questions

• A specific question is a question that you can
  phrase easily and one for which you will
  recognize the answer when you find it.
• An exploratory question is an open-ended question
  that can be harder to phrase it is also
  difficult to determine when you find a good
  answer.

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Specific Question
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Exploratory Question
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Web Search Process
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Web Search Strategy

• You may need to reformulate, or more clearly
  state, your question.
• Try to think of synonyms for each word.
• Identify unique phrases that relate to your topic
  or question.

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Using Search Engines

• Four Broad Categories Of Search Tools
• Search engines
• Directories
• Meta-search engines
• Other Web resources such as Web bibliographies

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Understanding Search Engines

• A web search engine is a Web site (or part of a
  Web site) that finds other Web pages that match a
  word or phrase you enter.
• The word or phrase you enter in a search engine
  is called a search expression or a query.
• A search expression or query might also include
  instructions that tell the search engine how to
  search.
• A search engine does not search the Web to find a
  match it searches only its own database of
  information about Web pages that it has
  collected, indexed, and stored.

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Understanding Search Engines

• A hit is a Web page that is indexed in the search
  engines database and that contains text that
  matches your search expression.
• Most search engines report the number of hits
  they find.
• All search engines provide a series of results
  pages, which are Web pages that contain
  hyperlinks to the Web pages that contain text
  that matches your search expression.

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Understanding Search Engines

• A Web robot, also called a bot or a spider, is a
  program that automatically searches the Web to
  find new Web sites and update information about
  old Web sites that already are in the database.
• Most search engines allow Web page creators to
  submit the URLs of their pages to search engine
  databases.
• Search engine operators often sell advertising
  space on the search engine Web page and on the
  results pages.

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Understanding Search Engines

• Some search engine operators sell paid placement
  rights on results pages. These paid placement
  links are often labeled as sponsored, and they
  are usually called sponsored links.
• If the advertising appears in a box on the page
  (usually at the top, but sometimes along the side
  or bottom of the page), it is usually called a
  banner ad.
• Revenue from sponsored links and banner ads is
  used to generate profit after covering the costs
  of maintaining the computer hardware and software
  required to search the Web and to create and
  search the database.

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Understanding Search Engines
HotBot search results for the search term car
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Using More Than One Search Engine

• Each search engine includes different Web pages
  in its database.
• Different search engines use different rules to
  evaluate search expressions.
• The best way to determine how a specific search
  engine interprets search expressions is to read
  the Help pages on the search engine Web site.
• Search engines change the way they interpret
  search expressions from time to time, so you
  should read the Help pages regularly.

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Understanding Search Engine Databases

• Search engine databases store different
  collections of information about the pages that
  exist on the Web at any given time.
• Each search engine database indexes the
  information it has collected from the Web
  differently.
• Search engine robots may collect information from
  a Web pages title, description, keywords, HTML
  tags, or read a certain number of words from each
  Web page.

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Understanding Search Engine Databases

• A META tag is HTML code that a Web page creator
  places in the page header for the specific
  purpose of informing Web robots about the content
  of the page.

META tags in a Web page

• Current Developments in
  Electronic Commerce
• and reports about electronic commerce
  developments."
• commerce, electronic data interchange, value
  added reseller, EDI, VAR, secure socket layer,
  business on the internet"

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Understanding Search Engine Databases

• Full text indexing when search engines store the
  entire content of every Web page they index.
• Stop words common words, such as and, the, it,
  and by, that many search engines omit from their
  databases.
• Many search engines include information about
  their search engines, robots, and databases on
  their Help or About pages.

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Search Engine Features

• Page ranking is a way of grading Web pages by the
  number of other Web pages that link to them. The
  URLs of Web pages with high rankings are
  presented first on the search results page.
• A natural language query interface allows users
  to enter a question exactly as they would ask a
  person that question.
• The procedure of converting a natural language
  question into a search expression is sometimes
  called parsing.

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Search Engine Features
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Using Directories and HybridSearch Engine
Directories

• A Web directory is a listing of hyperlinks to Web
  pages that is organized into hierarchical
  categories.
• The difference between a search engine and a Web
  directory is that people select the Web pages to
  include in a Web directory.
• Many directories allow a Web page to be indexed
  in several different categories.
• The main weakness of a directory is that you must
  know which category is likely to yield the
  information you desire.
• Yahoo! is one of the oldest and most respected
  directories on the Web.

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Using Directories and HybridSearch Engine
Directories
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Using Directories and HybridSearch Engine
Directories

• The combination of search engine and directory is
  sometimes called a hybrid search engine
  directory.
• Using a hybrid search engine directory can help
  you identify which category in the directory is
  likely to contain the information you need.
• After you enter a category, the search engine is
  useful for narrowing a search even further. You
  can enter a search expression and limit the
  search to that category.

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Using Meta-Search Engines

• A mega-search engine is a tool that combines the
  power of multiple search engines.
• Some meta-search tools also include directories.
• Because each search engine on the Web has
  different strengths and weaknesses, you might
  need to use several individual search engines to
  perform a complete search for a particular
  question.
• Using a meta-search engine lets you search
  several engines at the same time.
• Profusion, a popular meta-search engine, routes
  search terms to more than ten search engines and
  Web directories.

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Using Meta-Search Engines
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Using Other Web Resources

• Other Web resources are similar to bibliographies
  in that they contain lists of hyperlinks to Web
  pages.
• Many of these resources include summaries or
  reviews of Web pages.
• They are often called Web bibliographies, but
  many other names are used for them
• Resource lists
• Subject guides
• Clearinghouses
• Virtual libraries

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Using Other Web Resources

• Other web resources are sometimes confusingly
  called Web directories.
• Web bibliographies are usually more focused on
  specific subjects than Web directories, and Web
  bibliographies usually do not include a tool for
  searching within their categories.
• These other resources can be very useful when you
  want to obtain a broad overview or a basic
  understanding of a complex subject area.
• Some Web bibliographies are general references.
  Most are more focused. Many are created by
  librarians at university and public libraries.

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Boolean Logic andFiltering Techniques

• The most important factor in obtaining good
  results in a Web search is careful selection of
  the search terms you use.
• You can usually choose one or two words that will
  work well when the object of your search is
  straightforward.
• More complex search questions require more
  complex queries, which you can use along with
  Boolean logic, search expression operators, or
  filtering techniques, to broaden or narrow your
  search expression.

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Boolean Operators

• Boolean algebra was developed by George Boole, a
  nineteenth century British mathematician.
• Boolean operators, or logical operators, specify
  the logical relationship between the elements
  they join.
• Three basic Boolean operatorsAND, OR, and
  NOTare recognized by most search engines.
• You can use these operators in many search
  engines by including them with search terms.

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Boolean Operators
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Other Search Expression Operators

• A precedence operator, also called an inclusion
  operator or a grouping operator, clarifies the
  grouping within a complex expression and is
  usually indicated by the parentheses symbols.
• A location operator, or proximity operator, lets
  you search for terms that appear close to each
  other in the text of a Web page. The most common
  location operator offered in Web search engines
  is the NEAR operator.

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Wildcard Characters

• Most search engines support some use of a
  wildcard character in their search expressions.
• A wildcard character allows you to omit part of a
  search term.
• Many search engines recognize the asterisk () as
  the wildcard character.

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Search Filters

• Many search engines allow you to restrict your
  search by using search filters.
• A search filter eliminates Web pages from a
  search.
• The filter criteria can include such Web page
  attributes as language, data, domain, host, or
  page component.

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Complex Searches

• Most search engines implement many of the
  operators and filtering techniques you have
  learned about.
• Some search engines provide separate advanced
  search pages for these techniques.
• Some search engines allow you to use advanced
  techniques such as Boolean operators on their
  simple search pages.

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Using AltaVistaAdvanced Search

• Open the AltaVista search engine in your Web
  browser.
• Select the Advanced Search option.
• Formulate and enter a suitable search expression.
• Click the Find button.
• Evaluate the results and, if necessary, revise
  your search expression.

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Using AltaVista Advanced Search
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Filtered Search in HotBot

• Open the HotBot search engine page in your Web
  browser.
• Select the HotBot Advanced Search link.
• Formulate and enter a suitable search expression.
• Set any filters you want to use for the search.
• Click the SEARCH button.
• Evaluate the results and, if necessary, revise
  your search expression.

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Filtered Search in HotBot
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Filtered Search in Google

• Open the Google search engine page in your Web
  browser.
• Click the Advanced Search link.
• Formulate and enter suitable search expression
  elements.
• Formulate and set appropriate search filters.
• Click the Google Search button.
• Evaluate the results and, if necessary, revise
  your search expression.

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Filtered Search in Google
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Search Engines withClustering Features

• Vivísimo is a search engine that uses advanced
  technology to group its results into clusters.
• The clustering of results provides a filtering
  effect.
• The filtering is done automatically by the search
  engine after it runs the search.

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Obtaining Clustered Search Results Using Vivísimo

• Open the Vivísimo search engine page in your
  browser.
• Formulate and enter a suitable search expression.
• Click the Search button.
• Evaluate the results and, if necessary, revise
  your search expression.

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Obtaining Clustered Search Results Using Vivísimo
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Future of Web Search Tools

• A number of different companies and organizations
  are working on ways to make searching the Web
  easier.
• Work on natural language interfaces continues as
  search engine sites strive to make the job of
  searching even easier for users.
• An increasing number of search engines offer
  natural language querying as an option for
  entering search expressions.

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Using People to EnhanceWeb Directories

• One company, About.com, hires people with
  expertise in specific subject areas to create and
  manage their Web directory entries in those
  areas.
• The Open Directory Project uses the services of
  more than 40,000 volunteer editors who maintain
  listings in their individual areas of interest.
• The Open Directory Project offers the information
  in its Web directory to other Web directories and
  search engines at no charge.

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Evaluating the Validity and Quality of Web
Research Resources

• Information on the Web is seldom subjected to the
  review and editing processes that have become a
  standard practice in print publishing.
• The risks of obtaining and relying on inaccurate
  or unreliable information can be significant.
• Reduce your risk by carefully evaluating the
  quality of any Web resource on which you plan to
  rely for information related to an important
  judgment or decision.
• Evaluate on the Web pages authorship, content,
  and appearance.

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Author Identity and Objectivity

• Web page should identify the author and present
  the authors background information and
  credentials.
• Check secondary sources for corroborating
  information.
• Author contact information should be provided.
• Examine the domain identifier in the URL.
• Consider whether the qualifications presented by
  the author pertain to the material that appears
  on the Web site.
• Information about the authors affiliations
  should be provided.

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Content

• Determine timeliness of the content by checking
  the publication date.
• Read the content critically and evaluate whether
  the included topics are relevant to the research
  question at hand.
• Determine whether important topics or
  considerations were omitted.
• Assess the depth of treatment the author gives to
  subject.

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Form and Appearance

• Many pages that contain low-quality or incorrect
  information are poorly designed and not well
  edited.
• A Web page that contains spelling errors
  indicates a low-quality resource.
• Loud colors, graphics that serve no purpose, and
  flashing text are all Web page design elements
  that often suggest low-quality resource.

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Summary

• You learned how to formulate specific and
  exploratory research questions.
• You learned how to use a structured Web search
  process to find information on the Web.
• You learned how to develop search expressions and
  used them in search engines, Web directories, and
  meta-search engines.

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Summary

• You learned what Boolean operators, precedence
  operators, and location operators are and how
  they work in several major search engines.
• You learned how to use wildcards in search
  expressions.
• You learned how to use several types of filtering
  techniques to narrow your search results.

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Summary

• You learned how to evaluate the validity and
  reliability of a Web page by using information
  about author identity and objectivity.
• You learned how to evaluate the validity and
  reliability of a Web page by evaluating content,
  form and appearance.