SEARCH ENGINE

Using Search Engines to Find Information on the Web

INTRODUCTION:

                                Computer and internet are two important inventions that have created a number of facilities for human beings. All of its services are important but information search is a very useful service that has made easy for general public to gain

global knowlege sitting in any corner of the globe. Internet contains large amount of data about different topics in the shape of web pages. But we will have to use search engine to find various information on the world wide web.

What is search engine
A sarch engine is a website having search engine software. Search engine provide the facility to find the required websites about any particular topic on the internet by using keywords specified by the user.

 There are several types of search engines and searches may cover titles of documents, URL's, headers, or full text. Keep in mind that the results you get from one search engine may not match the results you get from another search engine. In fact, they are often different due to the way each search engine behaves. Therefore, it may actually be beneficial to use more than one search engine on a regular basis.

How web search engines work

A search engine operates in the following order:

1. Web crawling
2. Indexing
3. Searching^[10]

Web search engines work by storing information about many web pages. These pages are retrieved by a Web crawler (sometimes also known as a spider) — an automated Web browser which follows every link on the site.
 The contents of each page are then analyzed to determine how it should be indexed (for example, words can be extracted from the titles, page content, headings, or special fields called meta tags). Data about web pages are stored in an index database for use in later queries. The purpose of an index is to allow information to be found as quickly as possible.
When a user enters a query into a search engine (typically by using keywords), the engine examines its index and provides a listing of best-matching web pages according to its criteria, usually with a short summary containing the document's title and sometimes parts of the text. The index is built from the information stored with the data and the method by which the information is indexed.

    ^] Most search engines support the use of the boolean operators AND, OR and NOT to further specify the search query. Boolean operators are for literal searches that allow the user to refine and extend the terms of the search. The engine looks for the words or phrases exactly as entered.

Some search engines provide an advanced feature called proximity search which allows users to define the distance between keywords.^[10]
There is also concept-based searching where the research involves using statistical analysis on pages containing the words or phrases you search for. As well, natural language queries allow the user to type a question in the same form one would ask it to a human. A site like this would be ask.com.

The usefulness of a search engine depends on the relevance of the result set it gives back. While there may be millions of web pages that include a particular word or phrase, some pages may be more relevant, popular, or authoritative than others. Most search engines employ methods to rank the results to provide the "best" results first. How a search engine decides which pages are the best matches, and what order the results should be shown in, varies widely from one engine to another.^[10] The methods also change over time as Internet usage changes and new techniques evolve.
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Most Web search engines are commercial ventures supported by advertising revenue and, as a result, some employ, the practice of allowing advertisers to pay money to have their listings ranked higher in search results. Those search engines which do not accept money for their search engine results make money by running search related ads alongside the regular search engine results. The search engines make money every time someone clicks on one of these ads.

Market share

Search engine	Market share in May 2013
Google	82.80%
Yahoo!	6.42%
Baidu	4.89%
Bing	3.91%
Yandex	1.7%
Ask	0.52%
AOL	0.3%

Search engine bias

Although search engines are programmed to rank websites based on their popularity and relevancy, empirical studies indicate various political, economic, and social biases in the information they provide.^[17][18] These biases could be a direct result of economic and commercial processes (e.g., companies that advertise with a search engine can become also more popular in its organic search results), and political processes (e.g., the removal of search results in order to comply with local laws).^[19] Google Bombing is one example of an attempt to manipulate search results for political, social or commercial reasons.