How The Search
Engine Works?
Search Engine refers to a huge database of internet
resources such as webpages, newsgroups, programs, images etc. It helps to
locate information on World Wide Web.
Webcrawler
It is also known as
spider or Googlebots. It is a software component that traverses the web to
gather information.
Search
Engine Working
Webcrawler, database and the search interface are the major
component of a search engine that actually makes search engine to work. Search
engines make use of Boolean expression AND, OR, NOT to restrict and widen the
results of a search. Following are the steps that are performed by the search
engine:
The search engine looks for the keyword in the index for
predefined database instead of going directly to the web to search for the
keyword.
It then uses software to search for the information in the
database. This software component is known as webcrawler.
Once web crawler finds the pages, the search engine then
shows the relevant webpages as a result. These retrieved webpages generally
include title of page, size of text portion, first several sentences etc.
These search criteria may vary from one search engine to the
other .The retrieved information is ranked according to various factors such as
frequency of keywords, relevancy of information, links etc.
A crawler is a program that naturally looks through reports
on the Web. Crawlers are fundamentally customized for monotonous activities
with the goal that browsing is automated. Search engines use crawlers most
frequently to peruse the web and build an index. Different crawlers search
various kinds of data, for example, RSS channels and email addresses. The term
crawler originates from the main search engines on the Internet: the Web Crawler.
Synonyms are likewise "Bot" or "spider." The most known
webcrawler is the Googlebot.
Search engines are the door of simple access data; however
web crawlers, their little-known sidekicks, assume a pivotal job in gathering
together online content. In addition, they are fundamental to your search
engine optimization (SEO) strategy.
The crawling process begins with a list of web addresses
from past crawls and sitemaps provided by website owners. As our crawlers visit
these websites, they use links on those sites to discover other pages. The
software pays special attention to new sites, changes to existing sites and
dead links. Computer programs determine which sites to crawl, how often and how
many pages to fetch from each site.
We offer Search Console to give site owners granular choices
about how Google crawls their site: they can provide detailed instructions
about how to process pages on their sites can request a recrawl or can opt out
of crawling altogether using a file called “robots.txt”. Google never accepts
payment to crawl a site more frequently — we provide the same tools to all
websites to ensure the best possible results for our users.
Finding
information by crawling
The web is like an ever-growing library with billions of
books and no central filing system. We use software known as web crawlers to
discover publicly available webpages. Crawlers look at webpages and follow
links on those pages, much like you would if you were browsing content on the
web. They go from link to link and bring data about those webpages back to
Google’s servers.
Organizing
information by indexing
When crawlers find a webpage, our systems render the content
of the page, just as a browser does. We take note of key signals — from
keywords to website freshness — and we keep track of it all in the Search
index.
The Google Search index contains hundreds of billions of
webpages and is well over 100,000,000 gigabytes in size. It’s like the index in
the back of a book — with an entry for every word seen on every webpage we
index. When we index a webpage, we add it to the entries for all of the words
it contains.
With the Knowledge Graph, we’re continuing to go beyond
keyword matching to better understand the people, places and things you care
about. To do this, we not only organize information about webpages but other
types of information too. Today, Google Search can help you search text from
millions of books from major libraries, find travel times from your local
public transit agency, or help you navigate data from public sources like the
World Bank.
Examples of
a crawler
The most well-known crawler is the Googlebot, and there are
many additional examples as search engines generally use their own web
crawlers. For example
·
Bingbot
·
Slurp Bot
·
DuckDuckBot
·
Baiduspider
·
Yandex Bot
·
Sogou Spider
·
Exabot
·
Alexa Crawler
How do web
crawlers affect SEO?
SEO stands for search engine optimization, and it is the discipline of readying content for search indexing so that a website shows up
higher in search engine results.
If spider bots don't crawl a website, then it can't be
indexed, and it won't show up in search results. For this reason, if a website
owner wants to get organic traffic from search results, it is very important
that they don't block web crawler bots.
Significance
for search engine optimization
Web crawlers like Googlebot achieve their purpose of
ranking websites in the SERP through crawling and indexing. They follow
permanent links in the WWW and on websites. Per the website, every crawler has a
limited timeframe and budget available. Website owners can utilize the crawl
budget of the Googlebot more effectively by optimizing the website structure
such as navigation. URLs deemed more important due to a high number of
sessions and trustworthy incoming links are usually crawled more often. There
are certain measures for controlling crawlers like the Googlebot such as the
robots.txt, which can provide concrete instructions not to crawl certain areas
of a website, and the XML sitemap. This is stored in the Google Search Console,
and provides a clear overview of the structure of a website, making it clear
which areas should be crawled and indexed.