Instructor: Kathleen Scheaffer Content: Adopted from Gwen Harris

Transcription

1 WEB SEARCHING Instructor: Kathleen Scheaffer Content: Adopted from Gwen Harris - unless otherwise noted Agenda Introduction Definition of Search Engine, Invisible Web, Subject Directory and Portals Major Search Engines How Search Engines Work Web Searching Strategies Comparison of Search Engines Trends and Issues with Search Engines 1

2 Search Engine Search engines are huge databases of web page files that have been assembled automatically. There are two types of search engines: 1. Individual/General: compile their own searchable databases on the web. 2. Meta: do not compile databases. you submit keywords in its search box, and it transmits your search simultaneously to several individual search engines and their databases of web pages. Major Search Engines Google Live Search Yahoo Search Ask 2

3 Major Meta-Search Engines Dogpile Clusty Clusty 3

4 Web Directories There are two ways to use subject directories: you may browse or search. 1. Browse: follow the hierarchy of categories deeper and deeper, until you find the match to your question. Browsing often turns up serendipitous finds. 2. Search: look for the key words in the name of the category and/or the name of the site. Yahoo Directory Google Directory InfoMine About.com Librarian s Internet Index Portals Portals are gateways to many services Yahoo* Google * yahoo/review.html 4

5 Invisible/Deep Web +LPUgxQd88&feature=related How Search Engines Work Trawl the Web (spiders, crawlers, robots ) Collect Records Index Records Search Index Present Results 5

6 How Search Engines Rank Popularity Ranking Relevancy Ranking Factors: Title Tag Anchor Text of Links Keyword in Text Accessibility Links to Document from Site-Internal Pages Primary Subject Matter of Site External Links Link Popularity * Searcher Define the Question Choose the Appropriate Search Engine Choose the Appropriate Search Strategy Correct Syntax Assess the Results Refine the Search (if necessary) Assess the Results 6

7 Search Mechanisms Keywords and phrases Boolean Operators Proximity Searches Field Searching Stop Words Limiters Google History How Google works Implied AND Stop words : the, is, on, or, of, how, why, as well as certain single digits and single letters Case insensitive, site:, -, *, +, ~ Can use the operator OR site:, allintitle:, intitle:, intext:, allinurl:, inurl: filetype:, 7

8 Google Search Features Weather Stock Quotes Times Scores Calculator Translation Spell Checker Unit Conversion Google s Strengths and Weaknesses Strengths Size and breadth of content Language and regional versions. Several personal search services - Web history Weaknesses No nesting and limited Boolean May search for variants * 8

9 Google Exercises 1. You want to find results with ischool in the URL. Additionally, you only want documents that are pdfs. What are two ways to search? 2. You are interested in finding information on Chun Wei Choo; however, you only want results from the Faculty of Information s website. How do you search for him via Google search? 3. You are interested in what the weather is like in Berlin. What should you type in the search box? 4. You are not sure the conversion of liters to quarts? Yahoo History How Yahoo Ranks Results Implied AND -, +, OR, site:, link:, url:, inurl:, intitle: originurlextention: 9

10 Yahoo Shortcuts Map Weather Define News Zip code Calculator Airport Information * Yahoo Strengths and Weaknesses Strengths Search Assist for exploring concepts Second largest database Good shortcuts Site Explorer for getting more information about links and sites (specialty use) Weaknesses File type search uses originurlextension: rather than filetype:* Yahoo Answers are included in search results (Junk) * 10

11 Yahoo Exercises Search for universities that are in Ontario, Canada? What are some things to consider? You want the definition of zeitgiest. How do you go about finding one? Search for France in the url. How many results did you get? Go back to Advance Search, limit your search to pages written in English, pages updated within the past 3 months and the country to United States. How many results did you get? Live Search History Case insensitive OR, NOT,, -, +, Intitle:, site:, contains:wma, filetype:, loc:, prefer:, feed:, url: 11

12 Live Search Instant Answers Conversions Definitions Weather Financial Quotes Statistical Information * Live Search Strengths and Weaknesses Strengths Large Cached copies of web pages Automatic local search options Weaknesses Limited to 150 characters in a query Advanced search is awkward Help section not very helpful * 12

13 Live Search Exercises 1. Keyword search ischool and limit results with utoronto as the domain. What was your syntax? 2. Repeat the search above, but limit your search to Canada as the country and English as the language? Did your results vary? 3. Go back to basic search interface. How would you search for HIV information in a pdf? Ask.com History OR, -,, intitle:, site:, country:, inurl:, filetype: + doesn t have an effect Automatic Truncation 13

14 Ask.com Features Maps Dictionary Conversions Movie Show times Weather Stock Quotes Binocular Site View * Ask.com Strengths and Weaknesses Strengths Features Binoculars Date Restriction Ask Eraser Revise Advance Search Weaknesses Smaller Database No URL Submission No cached copies of pages * 14

15 Ask.com Exercises Search for information on the bird flu. Exclude the United States and limit your search to pages that were updated in the last 2 years. Get a definition for syntax. Comparison of results Open a tab for each of the search engines discussed Search for Joe Cox Compare results Repeat the search with Canada selected as the country. Now repeat the search; however, this time limit to utoronto.ca as the domain. Which search engine results do you prefer? Which search engine has the highest recall? 15

16 Discussion Which search engine do you prefer? Why? What is the most useful feature of this search engine? How many of you have used the advance search interface before? Now having engaged with it do you believe that you will, if you do not regularly, utilize it? When a search engine suggests other searchers is that useful? Search Engine Trends Google Zeitgeist: press/zeitgeist/index.html Yahoo Buzz: Ask IQ: Which engine is the most popular: google-searches-jan-09.php 16

17 Search Engine Issues Authority, credibility, currency, advertising Many users are only keyword searching Commercialization Lack of transparency Privacy Concerns How long are they storing our information? Who are they selling our information to? How the search results influence how we think, articulate and assess the concepts we are exploring ANY COMMENTS OR QUESTIONS? Feel free to contact me: 17