What
is Search Engine
Search
Engine allows to find a wide information from worldwide web on our search
term.
About SEO
Users
normally visit websites that are at the top of this record as they understand
those to be more appropriate to the issue. If you have ever considered why some
of these sites position better than the others then you must know that it is
because of a powerful web marketing technique called as search engine
optimization (SEO).
SEO
is a technique which allows search engines find and place your website higher
than the a lot of other sites in respond to a search term. SEO thus allows you
get traffic from search engines.
How Does Search Engine Works
First,
search engines crawl the Web to see what is there. This task is performed by a
piece of software, called a crawler or a spider (or Googlebot, as is the case
with Google). Spiders follow links from one page to another and index
everything they find on their way. Having in mind the number of pages on the
Web (over 20 billion), it is impossible for a spider to visit a site daily just
to see if a new page has appeared or if an existing page has been modified,
sometimes crawlers may not end up visiting your site for a month or two.
What you can
do is to check what a crawler sees from your site. As already mentioned,
crawlers are not humans and they do not see images, Flash movies, JavaScript,
frames, password-protected pages and directories, so if you have tons of these
on your site, you'd better run the Spider Simulator.
After a page
is crawled, the next step is to index its content. The indexed page is stored
in 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.
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. Since it
is likely that more than one page (practically it is millions of pages)
contains the search string, the search engine starts calculating the relevancy
of each of the pages in its index with the search string.
There are
various algorithms to calculate relevancy. Each of these algorithms has
different relative weights for common factors like keyword density, links, or
metatags. That is why different search engines give different search results
pages for the same search string. What is more, it is a known fact that all
major search engines, like Yahoo!, Google, Bing, etc. periodically change their
algorithms and if you want to keep at the top, you also need to adapt your
pages to the latest changes. This is one reason (the other is your competitors)
to devote permanent efforts to SEO, if you'd like to be at the top.
The last
step in search engines' activity is retrieving the results. Basically, it is
nothing more than simply displaying them in the browser – i.e. the endless
pages of search results that are sorted from the most relevant to the least
relevant sites.
