Week 3 - MKTG 348 - Search Engine Types and How They Work

When searching for something on Google or Yahoo!, how do they come up with their list of results?  Search engines rank their results based on what a user typed in the search bar.  When it comes to ranking results, there are two categories: crawler based and human powered based.  Web crawling is a program that scans the entire web to come up with webpages for your results.  They do this by evaluating each web page and comparing it to your search.  Crawling takes into account keywords, titles, body pages, etc.  Human powered directories works by humans putting in a description of their site to the search engine.  Say a small company has a website they just created, a worker can create their own description of their site, which the directory will use when a search is being conducted.


Web crawling is more commonly used, especially in the bigger search engines like a Google.  Crawling is made up of three processes: crawl the web, index pages, and search engine software to bring it on home to the users.  Indexing takes place right after the crawling process.  An index is a copy of a web page that is in a database.  Once the web page is indexed, it can be seen in search results.  What is really neat about the index is that if a web page is changed, the indexed page is automatically updated.  The last step in a crawler based search is the search engine itself.  The search engine takes all the indexed pages it received and picks the relevant content that closely matches the search.  The search engine basically picks out the content it believes matches the search and ranks them based on their perceived strength of correlation.