How search engines work ?

How search engines work ?

How search engines work ?

Please note: search engines are not simple. They include incredibly detailed processes and methodologies, and are updated all the time. This is a bare bones look at how search engines work to retrieve your search results. All search engines go by this basic process when conducting search processes, but because there are differences in search engines, there are bound to be different results depending on which engine you use.

1. The searcher types a query into a search engine.
2. Search engine software quickly sorts through literally millions of pages in its database to find matches to this query.
3. The search engine's results are ranked in order of relevancy.

Examples of Search Engines

There are a TON of great search engines out there for you to choose from. Whatever your search need might be, you'll find a search engine to meet it.



Source

 Three type of search engines

1. Directory  search engine

Internet search engines are categorized by topic in our searchable directory of general and specialty search engines. Also listed are resources and tools for exploring the deep web, performing advanced research, and for learning about using search engine tools and technology. Example Yahoo

2.General search engine

A general search engine is a search engine that covers the overall Web, using its own spider to collect Web pages for its own index.

When to use a general search engine

• When you have a well-defined topic or idea to research
• When your topic is obscure
• When you are looking for a specific site
• When you want to search the full text of millions of Web pages
• When you want to retrieve a large number of Web sites on your topic
• When you want to search for particular types of documents, sites, file types, languages, date last modified, geographical location, etc.

Examples of general search engines

This is easy. General search engines have been popular and newsworthy for many years.

• Google
• Bing
• Yahoo! 

3.Meta search engine

A metasearch engine is a search tool^[1] that sends user requests to several other search engines and/or databases and aggregates the results into a single list or displays them according to their source. Metasearch engines enable users to enter search criteria once and access several search engines simultaneously. Metasearch engines operate on the premise that the Web is too large for any one search engine to index it all and that more comprehensive search results can be obtained by combining the results from several search engines. This also may save the user from having to use multiple search engines separately.

The term "metasearch" is frequently used to classify a set of commercial search engines, see the list of search engines, but is also used to describe the paradigm of searching multiple data sources in real time. The National Information Standards Organization (NISO) uses the terms Federated Search and Metasearch interchangeably to describe this web search paradigm.