Search Engine Basics

This week in class we began to prepare for our SEO certification. The topics we covered were search engine basics, search engine market share, major search engines and directories, and search provider relationships.

So what is a Search Engine?  “A program that searches for and identifies items in a database that correspond to keywords or characters specified by the user, used especially for finding particular sites on the World Wide Web.”  Search Engines were developed because users needed to find relevant information from the vastness of the world wide web.  The internet was being used more and more often on a daily basis and this was crucial for making it usable.  The number one online activity is checking email, and the second is using search engines.  84% of internet users have used search engines.  

Google is market leader in the search engine industry, and Yahoo places second.  Both Google and Yahoo are crawler based search engines.  Yahoo was once a human based directory, but switched over to a crawler based in 2002.  

There are four major search engines:  Google, Yahoo, Ask, and Bing.  Google is the most popular search engine.  Yahoo started out as a subject directory only and then branched out and became a search engine.  Initially, Yahoo was powered by Google, but eventually began using their own algorithms and own technology.  Bing is a search engine by Microsoft.  It used other vendor’s databases and in 2005 it began using its own and also linked to Microsoft’s Encarta Encyclopedia content.  Ask is the final leader in search engines.  They built their own database without borrowing from Google.  They do however, show Google AdWords results in a sponsored link area.  

What is a Web Directory?  A web search tool compiled manually by human editors.  In the beginning, Yahoo was only a directory and eventually became a search engine.  Human editors create directories by sorting through submitted sites.  Search engines do it automatically.  Search engines are run by crawlers that read the information on a page and determine the page’s purpose.  There are 5 types of directories:  human edited, user categorized, user classified, independently classified and pay per click (PPC).  DMOZ and Yahoo are the leading the directories today, it is because they are the largest.  

Search engines do not maintain and update their database, so they usually borrow from major search engines.  For example, Google.  Many search engines borrow results from Google’s SERP (search engine results page).  There are many relationships between the thousands of search engines that exist on the internet and their database counterparts.