Sunday, September 24, 2017

How do web search engines work?

(The Hindi Version of this article will be posted shortly, to appear as the latest one in this blog)


How do web search engines work?
They give you many relevant articles when you use a suitable query. You get good results if your query is "Chandragupta Maurya year of birth".
Chandragupta's name is not widely used nowadays; it refers to a famous emperor. Articles on him are widely referred to. The first search result I got was the Wikipedia article on the emperor, when I used the query shown above. 
I had however remembered the phrase “Gupta’s empire” and had once searched for "Gupta date of birth" using the search engine Bing. 
The first person reported by Bing was Yaana Gupta, a model and singer, and I was directed to the following site address

The next report was about Siddharth Gupta and I was directed to read the following article

A word like “Gupta” occurs in thousands of articles about many different people; so it is not a very useful query word. Please try a combination of two words as in "Shekhar Gupta".
You get a reference to the Wikipedia article on a well-known Indian journalist. A query containing two or three relevant words is usually effective. Search engines use software named crawler to search the World Wide Web and makes an indexed collection of URLs of web pages. Words that tell us what is in that web page are used in indexing. Words like ‘this’, ‘is’ and ‘that’ do not tell us much about the content of a web page and so are not used in indexing. If you give a query like "Shekhar Gupta", the search engine will examine its database and give URLs like the following one
https://en.wikipedia.org/wiki/Shekhar_Gupta
You will also see a few lines from each listed webpage. You can read them and decide if the webpage is relevant to you. Indexing makes search efficient and fast.
Another principle that search engines use is that an article in which the query words appear many times is likely to be more useful. In comparison, an article with one passing reference to the query words may not be very useful to you.

There is yet another principle which is used by search engines. It is best to give you well-known articles recognized by many people. If an article is well written and is useful, it is likely to be referred to by many websites. Search Engine Crawlers keep count of such “links”. Earning more “links” from other sites makes an article more “famous”! Search engines prefer to give you such “famous” articles.


There are over a hundred such principles that give people very useful Search Engine Results Pages (S. E. R. P.).  This technology makes all human knowledge available on every smart phone! All knowledge is yours for free, if you know how to use the search engines!

Srinivasan Ramani 

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