T171 Useful Stuff - Search engines

What is a search engine?

A search engine is an enormous index of the web pages available i.e. www.yahoo.com. The search engine itself usually consists of three parts:

• 1) A "spider" (also known as a "crawler" or a "bot") which goes and searches every WebPage that wishes to be searchable. To make a web page searchable the designer inserts HTML META tags in the start of the HTML code giving a description of content and keywords, the "spider" can then read this.
• 2) A program that creates the index from the "spider" results.
• 3) A program that receives the users search request then interrogates the index and returns the results to the user.

Actually there is a fourth way of getting your web page into the index and that is to submit it directly to the search engine, Yahoo employ people to look at and categorise web pages to their directory and some that are not deemed suitable are removed or not included.

Use of search engines

The use of search engines allows information that would be difficult to find ploughing though books to be available very quickly. However the quality of the information could be suspect unless it can be verified as coming from a reputable source. The Internet is an open network so anybody can post information therefore casting doubt on its integrity. Using search engines can be extremely time-consuming due to the volume of information produced from the search criterion.

To use the search engine first you will have to go to its site i.e. www.yahoo.com, www.lycos.com etc. Once there type in you desired search criterion and click search, the search engine now searches its database for matches and then displays the results. There will probably be many thousands of hits this can then be reduced by modifying the search criterion and re-searching. Most search engines have advanced features that allow the use of Boolean operators in the search criterion that will help in significantly reducing the amount of "hits".