Among the thousands of search engines, very few are famous. Thanks to their algorithm which helps the user to find most relevant information. As observed earlier, Google, Yahoo! and MSN are the top three search engines in the world. Other major search engines are Teoma, Excite, Ask Jeeves, AOL, HotBot, Alta Vista, Lycos etc.

The listing in these search engines can attract huge traffic to the website. Hence, it is very important for search engine optimizer to know which search engine is best and highly used. It is very important for researchers as well! For them well known, commercially backed search engines mean dependable results. These search engines are more likely to be well maintained and upgraded when necessary, to keep pace with the growing web.

There are 9 main features on which search engines can be evaluated. They are as below.

• Boolean: Boolean searching refers to how multiple terms are combined in a search.

  and      requires that both terms be found.
  or       lets either term be found
  not      means any record containing the second term will be excluded
  ( )       means the Boolean operators can be nested using parentheses
  +      is equivalent to AND, requiring the term; the + should be placed directly in front of the search term
  -      is equivalent to NOT and means to exclude the term; the - should be placed directly in front of the search term
  Operators can be entered in the case shown by the example.

  Examples:
  (salad and (lime or kiwi)) not nuts

  +salad –nuts lime kiwi

• Default: What happens when multiple terms are entered for a search using no Boolean operators, + or - symbols, phrase marks, or other specialized features.

  Example:
  Two terms could be processed as
  Two AND terms
  Two OR terms
  or “two terms” as a phrase

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