What is Search Engine Optimization (SEO)?
SEO is the process of getting (more) traffic from the free, organic or natural search results on search engines like Google, Yahoo!, Bing, etc.
SEO is an ongoing process not a one shot task and it has two parts: On-page and Off-page with more than 200 factors involved.
In SEO, on-page optimization refers to factors that have an effect on your Web site or Web page listing in natural search results (SERP). Control of these factors is by the website administrator and mostly related to website code and configuration. Some of these factors are keyword density, content, Title, meta tags, inbound links, etc.
Off-page optimization like on-page refers to factors that have an effect on your Web site or Web page listing in natural search results but these factors as are off-site and cannot be controlled by website administrator directly. Some of these factors are domain age, outbound links, links quality, link popularity and page rank.