Advanced Internet Searching - Presentation Transcript
Advanced Internet Searching Techniques
Internet Search Tools Different types and how to use them. The web offers the choice of dozens of different search tools, each with it’s own database, command language, search capabilities, and method of displaying results.
Types of Search Tools
The most commonly used search tools are
Search Engines
Subject Directories
Other search tools include
Targeted directories
Focused Crawlers
Portals
Vortals
Meta-tools
Value-added search services
Search Engines
Search tool most often used.
Finds web pages by using small, automated computer programs called spiders or crawlers.
Advantage – Sites are recorded and updated automatically so the database is HUGE.
Disadvantage – Search engines do not evaluate the web sites for content or accuracy.
Search Engines
Search engines are the preferred tool when you:
Are looking for something very specific
Need to pin down a quick fact or two
Need to know if any information exists at all on a subject
Want mass quantities of links, but are not concerned about quality control.
Examples – Search Engines
Google – www.google.com
Altavista - www.altavista.com
Lycos - www.lycos.com
Yahoo! Search – http://search.yahoo.com
Excite – www.excite.com
Alltheweb – www.alltheweb.com
Search Engines
Natural language search engines allow uses to submit search terms in English rather than using operators, quotes, +signs and other search terminology.
They evaluate proximity of terms, phrase recognition, capitalization and keyword occurrence in titles, subheads and text.
Lexxe – http://www.lexxe.com
Hakia – http://www.hakia.com
Powerset – http:// www.powerset.com
Subject Directories
A subject directory is a database of titles, citations, and websites organized by category.
Advantage – Most directories are edited, maintained and created by people.
Usually they are carefully evaluated and annotated for this reason.
Disadvantage – Typically include a smaller number of sites than a search engine due to the great amount of human effort involved.
Examples – Subject Directories
Open Directory Project - The largest, most comprehensive human-edited directory of the Web. It is constructed and maintained by a vast, global community of volunteer editors.
Closed model directories such as Yahoo! And LookSmart are pulled together by professional editors who select the links and set up the categories. The user generally gets high quality results
Subject Directories
Subject directories are organized and selective.
They are useful when you want to know more about broad-based subjects, such as
General topics
Popular topics
Targeted directories
Current events
Product information
Hybrids
Many search engines are now hybrids- search tools that have an engine as well as a directory.
Sometimes targeted directories are matched with focused crawlers to produce a very powerful hybrid search tool. (e.g. http:// www.FirstGov.gov
Metasearch Engines
Metasearches use multiple engines to look for your keywords.
Advantage – You have many search engines all looking for what you need. Great when you are looking for something that is hard to find.
Disadvantage – It’s hard to fine tune your search and narrow things down. Also, Metasearches can sometimes give you more information than what you need.
Examples - Metasearches
Beaucoup! – www.beaucoup.com
Clusty – http://clusty.com
Mamma , “the mother of all search engines”- www.mamma.com
Ixquick – www.ixquick.com
Special Search tools
Yahooligans – Made for ages 7-12, pages are hand picked to be appropriate for children. Not only will the content on these pages be monitored, but so are the ads that are displayed.
Froogle – Made for the frugal shopper, this offshoot of Google has engines that catalog products and finds you the cheapest price for a given item on the internet. It’s in it’s “beta” version so they are still working out some kinks.
How Search Engines Work
inserting the phrase - cat dog -, will result in pages that have:
The word cat in the document
The word dog in the document
The word cat and dog in the document .
Fine Tuning Your Search
Boolean Language
Boolean - A language that was created to interface with search engines on the internet to help narrow your search.
Uses AND, OR, and NOT (must be in caps.)
Example: “Clinton NOT Lewinsky” on Yahoo!
Math to the Rescue!
Power searching also uses math, the universal language.
Uses symbols of + and – and “”.
Example: “Clinton – Lewinsky” on Yahoo!
Google
Find pages containing the term in the title:
intitle:[search term]
Find pages with terms in the text:
allintext:[search terms]
Find similar pages to a certain website:
related:[insert URL]
Find pages with the term in the URL:
inurl:[insert search term]
Try it out!
All The Web
Find pages containing the term in the title:
title:[search term]
Find pages with the term in the URL:
url.all:[search term]
Invisible Web
Also called “deep web” consists of materials search engines will not or cannot index.
Usually consists of web-based databases or pdf files.
Example: American Memory Project : Jackie Robinson.
Invisible Web Resources
Google – The only traditional search engine that can recognize .pdf and .doc files.
Profusion – a Metasearch tool that lets you search .pdf files.
Search Tips
Step 1 – define the data you want
Step 2 – figure out where it’s likely to be found
Step 3 – select the search tool most likely to provide it
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