A search engine is a service that indexes,organises and often rates and reviews thewebsite. It is basically type of program that useskeyword to search for documents that relate tothese keyword and then puts the result found inthe order to relevance to the topic that wassearched for.

Examples :-

Google

Yahoo

Most search engine can be successfully completedwith the use of good search engine and thecorrect search word. Search engines for thegeneral web do not really search the world wideweb directly. Each one searches a database of thefull text of web pages selected from the billionsof web pages out of their residing on servers.When we search the web using a search engine,we are always searching a somewhat stale copy ofthe real web page. When we click on links providedin a search engines search result, then weretrieve from the server the current version ofthe page.

Crawler based seearch engine

Directories

Hybrid search engine

Meta search engine

Free-text Query search engine

Are search engine that use software programthat are called, “Spiders”, “Crawlers”, “Robots”,“Bots”. These programs can access thewebpages to categorize and analyze them andthen add them in the search engine data base,where any user can find them when searching.The crawler based search engines areconstantly updated with new webpages thatwould be available in their database.

Examples :-

1. Google

2. Yahoo

3. Ask.com

Google began In januaray 1996 as a research project.

Founded by Larry Page and Sergey Brin.

Most popular search engine

Google Inc. owned and operated

six Google Modular Data Centers

across the U.S., One in Chile,

One in Finland, One in Ireland,

One in Belgium, One in Singapore

and One on Taiwan.

Yahoo was founded by Jerry Yang and David Filo in January 1994.

Yaiceshoo full coverage lets us browser categories of news, where articles and resources have been hand-assembled by Yahho editors.

Yahoo! provides internet

communication services

such as Yahoo! Messenger

and Yahoo! Mail.

Ask.com (originally known as Ask Jeeves) isa question answering-focused web searchengine founded in 1995 by GarrettGruenerand David Warthen in Berkeley, California.

The original software was implemented by GaryChevsky from his own design.

Depend on the human factor where editors review the web page, the ones with good evaluation reach the directories and are scrolled through during a search.

These directories are notupdated automatically unless reviewed.

Example :-

A good example of a directorise is yahoo!

Open directory (www.dmoz.org)

The hybrid search engine are search engines with a related directory.

Most of the search engine are moving in this direction.

This is because they want to appeal to both kinds of users beginners and advanced users.

Example :-

Yahoo.com

Google.com

Meta search engine are programs that search a number of search engines at the same time.

Theoretically, they provide the best result because they search across various engines at the same time

These engines sometimes result in too many matches that could possibly overhelm the user.

Example :-

Metacrawler

Dogpile

Accept the query in the form of a text question and hence ensures specific result.

The strength of these search engines is that they provide a kavel of comfort to the user because the user interacts ina question and answer approach just like another human being.

Example :-

The best example of this is ask jeeves.