How SEO works?

Here is a interesting video on “How Search Works?” by Matt Cutts

SEO stands for “Search Engine Optimization.”

 It is the finest action of capturing traffic from the “free,” “organic,” “editorial” or “natural” search results on search engines.

All major search engines alike Google, Yahoo and Bing have primary search results.

On the other hand, web pages and other content such as videos or local listings are shown and ranked based on what the search engine considers most relevant to users.

The best part of SEO is that payment is not involved, as it's with paid search ads.