How Search Engine Works?
Search
engines perform several activities in order to deliver search results
Crawling -is the process of fetching all
the web pages linked to a web site. This task is performed by software, called
a crawler or a spider (or Google bot, as is the case with Google).
·Indexing -is the process of
creating index for all the fetched webpages and keeping them into a giant
database from where it can later be retrieved. Essentially, the process of
indexing is identifying the words and expressions that best describe the page
and assigning the page to particular keywords.
·Processing -When a search request
comes, the search engine processes it . i.e. it compares the search string in
the search request with the indexed pages in the database.
· Calculating Relevancy -Since it
is likely that more than one page contains the search string, so the search
engine starts calculating the relevancy of each of the pages in its index to
the search string.
·Retrieving Results -The last step
in search engines' activities is retrieving the best matched results.
Basically, it is nothing more than simply displaying them in the browser. Search
engines such as Google and Yahoo! often update their relevancy algorithm dozens
of times per month. When you see changes in your rankings it is due to an
algorithmic shift or something else outside of your control.
Although the basic principle of operation of all
search engines is the same, the minor differences between their relevancy algorithms
lead to major changes in results relevancy.
