How Search Engines Work ?

Most of us use search engines every day to search about particular query and search engines return some best results those are relevant to that query.Here we will see how search engines works?

Search engines work in three different phases

1. Web Crawling

Web search engine stores information about webpages which they retrieve from html itself.These pages are retrieved by web crawlers most of time we call as Spider.Web crawlers crawls site and follows each indexed link of every site.You can restrict these web crawlers from robot.txt which is made for these web crawlers. These crawlers then extract all the information about web page from title ,meta tags, headings & content and stores in database.

When user types a search query then first of all search engines check results in database file if they have already incurred query ,Google uses cache mechanism for that where they store result of search queries to minimize time.Increased search relevance makes these cached pages very useful, even beyond the fact that they may contain data that may no longer be available elsewhere.


When a user enters a query into a search engine (typically by using key words), 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. Unfortunately, there is not one search engine that allows to search documents by date. 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. 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

Working of Search Engine is shown as below,

How Search Engine Work


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. The methods also change over time as Internet usage changes and new techniques evolve. There are two main types of search engine that have evolved: one is a system of predefined and hierarchically ordered keywords that humans have programmed extensively. The other is a system that generates an “inverted index” by analyzing texts it locates. This second form relies much more heavily on the computer itself to do the bulk of the work.


This is the process by which post of the search engines work now a days though we see many changes in algorithm and searching mechanism ,every search engine is focused on relevancy and better load time.

Know your competitors by SEO for Firefox

Before we start optimizing for the SEO for a certain page it is very important to understand

  • Target Market (Audience)
  • Market potential
  • Market Growth
  • Competitors

To start a preliminary research on competitors we should know our strength and weakness for a market and then we keep eye on competitor’s activity.

SEO for Firefox:

SEO for Firefox is a best tool to get a at a glance details for the competitors those we want to track ,this is a Firefox extension and works a better for preliminary information about the competitors ,


After installing it to your Firefox you are ready to use it .It gives information about

  • PR: (Google PageRank) an estimated measure of global link authority
  • Age: age pulled from, shows the first time a page was indexed by’s spider. The theory is that if found a page so did many of the major search engines.
  • Links: (Yahoo! linkdomain) shows a rough estimate of the total number of links pointing at a domain
  • .edu Link: (Yahoo! .edu linkdomain ) shows a rough estimate of the total number of .edu links pointing at a domain
  • .edu Page Link: (Yahoo! .edu link ) shows a rough estimate of the total number of .edu links pointing at a specific page
  • .gov Link: (Yahoo! .gov linkdomain ) shows a rough estimate of the total number of .gov links pointing at a domain
  • Page Links: (Yahoo! link) shows a rough estimate of the total number of links pointing at a page
  • number of times a URL has been bookmarked on Heavily skewed toward techy / Web 2.0 stuff.
  • Technorati: an estimate of the total number of links to a site from blogs
  • Alexa: rank based on website traffic . Heavily skewed toward internet marketing and webmaster related resources.
  • Cached: (Google site:) shows how many pages from a site are indexed in Google
  • dmoz: searches the Google Directory to count the total number of pages from a site that are listed in DMOZ, and the total number of pages listed in DMOZ that reference that URL.
  • Bloglines: shows you how many people are subscribed to a particular blog via Bloglines.
  • is a site listed in the Yahoo! Directory or not.
  • WhoIs: makes it easy to look up the whois data for any site.



From this we can come to know about a preliminary necessary information about the site.

We can export this data in .csv .xlx format also.

We will see a competitive research later in coming posts by

  • Google
  • Semrush
  • OpensiteExplorer