1. Internet Basics How Search Engines Work?

2. Internet Search Engines  Special sites on the web to find information stored on other sites Key words Index of the words Spiders: special software robots used to build lists of the words found on Web sites. Web crawling: Process of building the list of websites

3. Web Crawling

4. Google  Academic search engine  Sergey Brin and Lawrence Page  Initial system: Use 3 or 4 spiders at a time 300 connections 100 pages/sec ~600 kb/sec data  Each spider looks for 2 things The words within the page Words in titles, subtitles, meta tags  Web in Plain English Web in Plain English

5. Search engine capabilities  Rated by the size of index  Large engines (Google) - use for obscure (vague) information  Yahoo – directory structure

6. Web Searches in Plain English

7. Common Search Commands  Quotation Marks (“) For example: "Martin Luther King"  Addition Sign(+) For example: + Florida + taxes  Subtraction Sign(-) For example: + Washington -DC  Asterisks(*) For example: Mexic* will look for Mexico, Mexican, Mexicali, etc.  Boolean Logic