What is SEO, How does SEO works.

Whenever Users enter a query in a search box of any search engine and hit 'enter' then a list of website link results that consists of that query terms are displayed. Users normally visit those websites which are at the top of this result list as these looks more relevant to the query term.Some of these websites are displayed always at the top, because of a powerful web marketing technique called Search Engine Optimization (SEO).

SEO can be thought as-

• Optimizing a website for Search Engines.
• The process of developing and designing a web site to get a better rank in search engine results for particular query term.
• To improve the volume and quality of traffic received  to a web site from search engines.
• To understand how search algorithms of any search engine work and what human visitors might search, so that website traffic can be increased.
• A technique of ranking your website higher than other millions of websites for a particular keyword search through search engines.

How Search Engine Works?

       Search engine provide search results for particular search term after performing several activities like crawling, indexing, processing, relevancy checking etc.

• Crawling the website -It is the process of fetching all the web pages from a web site. This task is performed by a software tool, called a web crawler or a web spider (Googlebot, in the case of Google). Web crawler fetches all the text, links and images in the form of TEXT from the web pages, and stores these fetched text in its database.
• Indexing the pages -It is the process of making index for all the fetched web pages in the database from where it can later be retrieved when required. Indexing is basically identifying the words and keywords that best describe a particular web page and then arranging (Indexing) the web page in database according to the keyword relevancy.
• Processing the search- When users search for some search phrase, then the words in the search phrase are compared to the words/keywords in search engine database. And then, according to search keyword's relevancy the web pages are indexed for that particular search term.
• Relevancy check- In a website, more than one page may contain the search term. So, to check which web page is highly relevant to the particular search term is the task of relevancy checking. At this stage, search engine starts checking relevancy of the pages in its index for different search phrases.
• Displaying Results - This is the last step of search engine's activity. In this step, the best  web page links which are highly relevant to the search phrase are displayed.

Types of applying SEO:

      There are basically two approaches to apply SEO for any website, that are- On page SEO and Off page SEO.

• On Page SEO- This includes optimizing the web page's contents like- providing good content, using good keywords, keyword placement at proper location, giving relevant and appropriate title to every web page etc.
• Off-Page SEO- This includes optimizing the other factors for web page like- link building, submitting links in open directories, exchanging links with other related websites etc.

Different search engines might change their relevancy algorithm many times a month, but the basic principle of operation of all the search engines is same. But the minor change change in their relevancy algorithm may lead to major changes in their search results relevancy. Different search engines may follow different factors for searching like for Google- Older is better, for Yahoo and Bing- On page factors are more important.