How does a search Engine work?

Basically, search engines are massive data bases that have all the information going around the Web.The web's most popular search engine is Google.
When you type a word or sentence, the search engine searches in its data base and gives back a list of results in an determinate order.
To search this information the Search engine uses (Spiders).
These collect all the info from all sites and pages,also following links from the sites.The always going around the net collecting new sites to update the results list.

These results are treated different by search engines; They use different ways of classifying the information and ranking web sites depending on the components and how the site positions.This is the way they determine the order of the results.

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How do search engines work?, How does Google work?, what are Internet spiders?, what is google bot?

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