Internet Tutorial 03

New Perspectives on The Internet, Sixth Edition—Comprehensive Tutorial 3

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XP

Searching the Web

Using Search Engines and

Directories Effectively

Tutorial 3


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XPObjectives

• 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 metasearch engines effectively.


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XPObjectives

• 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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XPTypes of Search Questions

• Specific question: a question that you can phrase easily and one for which you will recognize the answer when you find it.

• Exploratory question: an open-ended question that can be harder to phrase; it is also difficult to determine when you find a good answer.

Specific Question


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Exploratory Question


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Web Search Process


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XPWeb 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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XPUsing Search Engines

Four Broad Categories Of Search Tools:

1. Search engines

2. Directories

3. Metasearch engines

4. Other Web resources such as Web bibliographies


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XPUnderstanding Search Engines

• Search engine: a Web site (or part of a Web site) that finds other Web pages that match a word or phrase you enter.

• Search expression or query: the word or phrase you enter in a search engine.

• A search expression 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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• Hit: a Web page indexed in the search engine’s database that contains text that matches your search expression.

• Most search engines report the number of hits they find.

• Results pages: a list of Web pages in a search engine that contain hyperlinks to the Web pages that contain text that matches your search expression.


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• Web robot (bot or spider): 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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• Sponsored links: paid placement links on results pages.

• Banner ad: a sponsored link that appears in a box on the page (usually at the top, but sometimes along the side or bottom of the page).

• 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.

Understanding Search Engines

Google search results for the search term “car”


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XPUsing More Than One Search Engine

• Each search engine includes different Web pages in its database.

• Each 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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XPUnderstanding 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 page’s title, description, keywords, HTML tags, or read a certain number of words from each Web page.


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• Meta tag: 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.

<HEAD>

<TITLE>Current Developments in Electronic Commerce</TITLE>

<META NAME ="description" CONTENT= "Current news and reports about electronic commerce developments.">

<META NAME ="keywords" CONTENT ="electronic commerce, electronic data interchange, value added reseller, EDI, VAR, secure socket layer, business on the internet">

</HEAD>

META tags in a Web page


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• 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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XPSearch Engine Features

• Page ranking: a way of grading Web pages by the number of other Web pages that link to them.

• URLs of Web pages with high rankings are presented first on search results pages.

• Natural language query interface: allows users to enter a question exactly as they would ask a person that question.

• Parsing: the procedure of converting a natural language question into a search expression.

• Stemming: the use of the root form of a word to find results containing the root word and its variations, which are created by adding standard endings to the root word.

Search Engine Features


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Natural language query on Ask.com


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XPUsing Directories and HybridSearch Engine Directories

• Web directory: 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 Web 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.

Using Directories and HybridSearch Engine Directories


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Yahoo! Web directory


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XPUsing Directories and HybridSearch Engine Directories

• Hybrid search engine directory: the combination of search engine and 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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XPUsing Metasearch Engines

• Metasearch engine

a tool that lets you search several engines at the same.

does not have its own database of Web information

accepts a search expression and transmits it to several search engines, which run the search expression against their databases and then return results to the metasearch engine, which then reports consolidated results from all of the search engines it queried

• Mamma.com was one of the first metasearch engines on the Web.

Using Metasearch Engines


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Mamma.com was one of the first metasearch engines on the Web.

Using Metasearch Engines

• In the Kartoo metasearch engine, hits are shown as images each image is clustered around words that appear in the results pages.

• When the pointer is moved over a word, the links appear as lines between the word and the images.

• To refine a search, click a word to add it to the search expression.


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XPUsing Other Web Resources

• Web bibliographies: Web search tools that are similar to bibliographies in that they contain lists of hyperlinks to Web pages, but instead contain list of links to Web pages.

• Many of these resources include summaries or reviews of Web pages.

• Also called:• Resource lists• Subject guides• Clearinghouses• Virtual libraries


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XPUsing Other Web Resources

• Web bibliographies are sometimes confusingly called “Web directories.” are usually more focused on specific subjects than Web

directories usually do not include a tool for searching within their

categories.

• Web bibliographies 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, but most are more focused.

• Many Web bibliographies are created by librarians at university and public libraries.


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XPBoolean 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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XPBoolean 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 operators—AND, OR, and NOT—are recognized by most search engines.

• You can use these operators in many search engines by including them with search terms.


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XPBoolean Operators

Search Expression Search Returns Pages that Include

exports AND France AND Japan All of the three search terms

exports OR France OR Japan Any of the three search terms

exports NOT France NOT Japan Exports, but not if the page also includes the terms France or Japan

exports AND France NOT Japan Exports and France, but not Japan


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XPOther 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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XPWildcard Characters

• Wildcard character: allows you to omit part of a search term. most search engines support some use of

a wildcard character in their search expressions.

many search engines recognize the asterisk (*) as the wildcard character.


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XPSearch Filters

• 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.

many search engines allow you to restrict your search by using them.


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XPComplex 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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XPUsing 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.

Using AltaVista Advanced Search


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Complex search in AltaVista for the search expression:

Germany AND (trade or treat*) AND agricult*


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XPFiltered Search in Ask Jeeves

• Open the Ask Jeeves search engine page in your Web browser.

• Select the Advanced Options link.


• Set any filters you want to use for the search.

• Click the Ask button.


Filtered Search in Ask Jeeves


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Advanced search page in Ask Jeeves for the search expression:

rice harvest

Filtered to search only for pages from Southeast Asia and modified in the last six months


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XPFiltered 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.


Filtered Search in Google


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Advanced search page in Google for the search expression:

Finland “School of Economics”

Filtered to search only for pages in English and from the TLD .fi.


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XPSearch 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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XPObtaining Clustered Search Results Using Vivísimo

• Open the Vivísimo search engine page in your browser.


• Click the Search button.


Obtaining Clustered Search Results Using Vivísimo


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XPFuture of Web Search Tools

• Most search engines cannot search the deep Web (hidden Web or invisible Web). static Web page: an HTML file that exists on a Web server dynamic Web page: a Web page generated as a result of

a user’s query dynamic Web pages are not stored permanently on a Web

server and cannot be found by bots much of the content on dynamic Web pages is accessible

only by logged in users • Work on natural language interfaces continues as

search engine sites strive to make the job of searching even easier for users.


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XPUsing People to EnhanceWeb Directories

• 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. offers the information in its Web directory to other Web

directories and search engines at no charge many major Web directories, search engines, and

metasearch engines regularly download and store the Project’s information in their databases.


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XPEvaluating 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 page’s authorship, content, and appearance.


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XPAuthor Identity and Objectivity

• Web pages should identify the author and present the author’s 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 author’s affiliations should be provided.


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XPContent

• 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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XPForm 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 might indicate 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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XPEvaluating the Quality of a Web Site

• Open the Web page in your Web browser.

• Identify the author, if possible. If you can identify the author, evaluate his or her credentials and objectivity.

• Examine the content of the Web site.

• Evaluate the site’s form and appearance.

• Draw a conclusion about the site’s overall quality.


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XPSummary

• 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 metasearch engines.


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XPSummary

• 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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XPSummary

• 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.

Technology

Internet Tutorial 03