What is a Search Engine? | How does a search engine work? | Popular examples of search engines

A search engine is an application which is used to find the information from the web servers. We just provide some keywords to search engine, and in return the search engine provides us the information we need.

In this post, we will cover the following contents:

  • What is a search engine?
  • Popular examples of search engines.
  • What are the different types of Search Engines?
  • How does search engine works?
  • How to use the search engine effectively?

WHAT IS A SEARCH ENGINE?

A search engine is a software system which is designed to search the World Wide Web in a specified way for getting the information specified in search query. Popular examples of search engines are Google, Bing, Yahoo, DuckDuckGo etc; 

WHAT ARE POPULAR EXAMPLES OF SEARCH ENGINES?

The most popular examples of search engines are provided below:
  • Google 
  • Bing 
  • Yahoo 
  • Baidu 
  • Yandex 
  • DuckDuckGo 
  • Ask.com 
  • AOL.com 
  • WolframAlpha 
  • Internet Archive

Search Market Share Worldwide

Search EngineShare Market
Google91.5%
Bing2.55%
Yahoo1.64%
Baidu1.44%
Yandex0.45%
DuckDuckGo0.28%
Ask.com0.23%
Aol.comNA
WolframeAlphaNA
Internet ArchiveNA


Google

It is the most popular search engine used worldwide. The most relevant results provided by the Google make it the most popular and trusted search engine. Other products are provided by Google company are Youtube, Google Drive, Google Maps, Gmail, etc.

Bing

The popular search engine after the Google is Bing. It is owned by the Microsoft which was originated to challenge Google in search results but despite their best efforts, they are not able to convince the users that Bing can be alternate to the Google. It is the default search engine on the Internet Explorer.

Yahoo

It is one of the popular search engines. It comes at the third place in search which share 2% of the market share.

Baidu 

It is the most popular search engine in Chine which was founded in 2000. Although it can be used from any region, yet it is available in the chinese language.

DuckDuckGo

Unlike Google and Yahoo, this search engine doesn't own its own search index. It relies on other data sources. The main thing of this search engine that makes it different from other search engines is that it doesn't store users data. For the privacy issues, users can make use of this search engine.

Ask.com

It is based on question and answers based format where most of the answers are provided by the users.

WHAT ARE THE DIFFERENT TYPES OF SEARCH ENGINES?


  • Crawler-Based Search Engines
  • Human-Powered Directories
  • Hybrid Search Engines Or Mixed Results
  • Meta Search Engine

Crawler-Based Search Engines

Crawler-based search engines, such as Google, create their listings automatically. They "crawl" or "spider" the web, then people search through what they have found.

Human-Powered Directories

A human-powered directory, such as the Open Directory, depends on humans for its listings. You submit a short description to the directory for your entire site, or editors write one for sites they review. A search looks for matches only in the descriptions submitted. 

Hybrid Search Engines Or Mixed Results

In the web's early days, it used to be that a search engine either presented crawler-based results or human-powered listings. Today, it extremely common for both types of results to be presented.

Meta Search Engine

These types of search engines don't own their own database. They rely on another search engines in a way. In these search engine, the user query provided by a user is further send to another multiple search engines. The retrieved results from the several search engines are further combined and generate a list. This final list is presented to user by Meta Search Engine.

HOW DOES SEARCH ENGINE WORK?

Search Engine mostly have four primary functions:
  • Crawling
  • Indexing
  • Ranking
  • Query Matching

Crawling

It is the process of discovering important pages on the web. Many bots are used by search engines for this purpose.

Indexing

It stores all the crawled pages with useful information known as tags for each web page.

Ranking

It ranks and sort the web pages with respect to the ranking of the web pages for relevant queries.

Let's understand the working of search engine in details.
In order to get the results from the web, a user submits query to search engine. The search engine initially pre-processes the user query. The pre-processing includes tokenization, stopwords removal, stemming, and spelling correction. 
After preprocesing, the preprocessed and tokenized keywords are matched directly (Query Matching) to indexer of the search engine. The most relevant web documents are fetched from the database and presented to the user sorted on the basis of the ranking of the web documents.

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