Search engine optimization (SEO) is the process of increasing the quality and quantity of internet traffic from search engines to a website or web page. SEO focuses on unpaid traffic (often known as “natural” or “organic” results) rather than sponsored or direct traffic. Unpaid traffic can come from a variety of sources, including image and video searches, academic and news searches, and industry-specific vertical search engines.

SEO evaluates how search engines work, the computer-programmed rules that govern search engine behavior, what people search for, the actual search phrases or keywords placed into search engines, and which search engines are preferred by their targeted audience as an Internet marketing strategy. SEO is done because websites that rank higher on search engine results pages (SERPs) gain more visitors from search engines. These visitors may then be converted into clients.