4 1 SEARCHING THE WEB Using Search Engines and Directories Effectively New Perspectives on THE INTERNET

4 2 Objectives Determine whether a research question is specific or exploratory Learn how to formulate an effective Web search strategy to answer research questions Learn about Web search tools and how they work Create various kinds of search expressions Find information using search engines, directories, and other Web research tools

4 3 Types of Search Questions You can use the Web to obtain answers to specific and exploratory questions. Specific questions can be phrased easily and you will recognize the answer when you find it. Exploratory questions are open-ended questions that can be harder to phrase. You must fan out in a number of directions to find relevant information.

4 4 Types of Search Questions Specific questions start with broad categories of information and gradually narrow the search until the answer is found. Figure 4-1

4 5 Types of Search Questions Exploratory questions start with general questions that lead to other, less-general questions.

4 6 Web Search Strategy

4 7 Web Search Tools There are four categories of Web search tools: Search engines Directories Meta-search engines Other Web resources

4 8 Using Search Engines A Web search engine is a special kind of Web site that finds other Web pages that match a word or phrase you enter. The word or phrase entered is called the search expression or query. A search engine does not search the Web to find a match; it only searches its own database of information.

4 9 Using Search Engines A hit is a Web page that is indexed in the search engine’s database and contains text that matches the query. Results pages are Web pages that contain hyperlinks to the Web pages that contain text that matches the search expression. A Web robot, or bot or spider, is a program that is used by search engines to automatically search the Web and update the search engine’s database.

4 10 Using Search Engines Each search engine includes different Web pages in its database. Search engines allow Web page creators to submit the URLs of their pages to search engine databases. Search engines use advertising revenue to generate profit. Some search engines return hits for pages that include all of the words entered in a search expression.

4 11 Using Search Engines

4 12 Using Search Engines

4 13 Using Search Engines 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. Figure 4-6

4 14 Using Search Engines Full text indexing – when search engines store the entire content of every Web page they place in their databases. Stop words – common words, such as and, the, it, and by, omitted by search engines from their databases. Page ranking is a way of grading Web pages by the number of other Web pages that link to them.

4 15 Using Search Engines

4 16 Using Search Engines Natural language query interface allows users to enter a question exactly as they would ask a person that question.

4 17 Using Search Engines 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. One of the oldest and most respected directories on the web is Yahoo! Hybrid search engine directory – a combination of search engine and directory

4 18 Using Search Engines

4 19 Using Search Engines To search the Web – Identify key search terms. Use a Web directory to find the answer. Examine the results and decide whether a second search using a different category or search terms is necessary. Plan to repeat the first three steps until you get an appropriate answer.

4 20 Using Search Engines

4 21 Using Search Engines

4 22 Using Search Engines Each search engine on the Web has different strengths and weaknesses because each search engine: Uses a different Web robot to gather information about Web pages. Stores a different amount of Web page text in its database. Selects different Web pages to index. Has different storage resources. Interprets search expressions somewhat differently.

4 23 Using Meta-Search Engines Meta-search engine – a tool that combines the power of multiple search engines. A meta-search engine accepts your search expression and transmits it to several search engines. The meta-search engine reports consolidated results from all the search engines it queried.

4 24 Using Meta-Search Engines

4 25 Using Other Web Resources Other web resources include: Resource lists Guides Clearinghouses Virtual libraries These resources are: Similar to bibliographies Can be a general reference or more focused

4 26 Using Other Web Resources

4 27 Using Other Web Resources

4 28 Boolean Logic and Filtering Techniques Careful selection the search terms is the most important factor in getting good results from a search engine. Use Boolean logic, search expression operators, or filtering techniques to broaden or narrow the search expression.

4 29 Boolean Operators 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.

4 30 Boolean Operators

4 31 Other Search Expressions Operators Precedence operator, or inclusion operator, or grouping operator, clarifies the grouping within a complex expression. Usually indicated by the parentheses symbols. Location operator, or proximity operator, searches for terms that appear close to each other in the text of a Web page. NEAR is the most common location operator.

4 32 Wildcard Characters and Search Filters A wildcard character allows you to omit part of the search term. Many search engines use the asterisk (*) as the wildcard character. A search filter eliminates Web pages from a search.

4 33 Advanced Searches Advanced Search in AltaVista – Open the AltaVista search engine in your Web browser. Select the Advance Search option. Choose a language filter. Formulate and enter a suitable search expression. Click the Search button. Evaluate the results, and if necessary, revise your search expression.

4 34 Advanced Searches

4 35 Advanced Searches

4 36 Advanced Searches Advanced Search in HotBot – Open the HotBot search engine in your Web browser. Open the HotBot Advanced Search page. Set the Look For field to allow Boolean operators. Select a date and geographic region filters. Formulate and enter a suitable search expression. Click the SEARCH button. Evaluate the results, and if necessary, revise your search expression.

4 37 Advanced Searches

4 38 Advanced Searches

4 39 Advanced Searches Advanced Search in Excite – Open the Excite search engine in your Web browser. Formulate and enter a suitable search expression. Click the Search button. Evaluate the results, and if necessary, revise your search expression.

4 40 Advanced Searches

4 41 Advanced Searches Advanced Search in Northern Light – Open the Northern Light search engine in your Web browser. Formulate and enter a suitable search expression. Click the Search button. Evaluate the results, and if necessary, revise your search expression.

4 42 Advanced Searches

4 43 Future of Web Search Tools More companies are working on natural language interfaces. 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 volunteer editors who maintain listings in their individual areas of expertise.