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1. Search Engine
Presented by
Shanta Rayamajhi Basnet
Roll.no. 76155010
Nepal Open University

2. Contents
 What is search engine?
 History of Search engine
 How does it work?
 Types of Search Engine
 Why Search Engine?
 Disadvantages of Search Engine

3. What is Search engine:
 A program that searches for and identifies items in a database
that correspond to keywords or characters specified by the
user, used especially for finding particular sites on the World
Wide Web.
 Online tools that helps user to search through vast data over
internet for a specific query.
 Examples: Google, yahoo, bing, duckduckgo ,etc.

4. History of Search Engines
 1990– The first search engine is Archie. However, the limited data
made only the listings available, not the content.
 1991– Tim Berners-Lee, the inventor of the WWW, created a virtual
library to help users find URLs for different websites.
 1993– Jump Station brought a new leap with their linear search which
showed a page’s title and header in the same results.
 1994– David Filo and Jerry Yang create Yahoo! Search. The site was
the first collection of web pages across the internet. They include man-
made descriptions for the URLs.

5. History of Search Engines
 1996- Larry Page and Sergey Brin created the predecessor to
Google BackRub.
 1998– Google officially launches.
 Today- Google have over 75 percent of the search market share.

6. How does it work?
 Scheduling
 Assesses the relative importance of new and known URLs.
 Decide when to crawl new URL.
 Crawling
 Downloads content of web pages.
 Passes downloaded webpage to parser.

7. How does it work? (cont. )
 Parsing
 Extracts links from the page, along with other key information.
 Sends extracted data for indexing.
 Indexing
 Adding information from crawler to Database called search index.
 digital library of information about trillions of web pages.

8. Types of Search Engines:
 Hybrids
 mix of crawlers and directories.
 Can choose whether to search the Web or a directory.
 Meta
 several other search engines at once and combines the results into one list.
 Dogpile
(Dogpile is a metasearch engine which collects search results from multiple
different search engines including Google, Yahoo, Bing and a few others)

9. How does it work? (cont. )

10. Types of Search Engines
 Crawlers
 These types of search engines use a "spider" or a "crawler" to search the
Internet.
 Google and Yahoo are examples of crawler search engines.
 Directories
 Human powered search engines.
 A website is submitted to the directory and must be approved for inclusion by
editorial staff.
 Open Directory Project and the Internet Public Library are examples of
directories.

11. Why Search Engine?
 Quick search in vast amount of data.
 Can search data according to user specified query.
 Can locate data that normally is very hard.
 Can search for specified format like using google dorks.
 Keeps internet/www in systematic order.

12. Limitations:
 May show tons of unrelated results.
 Matter of privacy as anyone with internet can search through search engine.
 Makes people more dependent.
 Make developers hard to hide some content that was not intended for
everyone.

13. References
 https://libguides.astate.edu/c.php?g=14516&p=78177
 https://en.wikipedia.org/wiki/Web_search_engine
 https://www.bigcommerce.com/ecommerce-answers/how-does-search-
engine-work/
 https://ahrefs.com/blog/how-do-search-engines-work/
 https://www.slideshare.net/AdarshkumarYadav/search-engine-72427771