Search engine optimization (SEO) is the process of increasing the visibility of a website or a web page to users of a web search engine.The term excludes the purchase of paid placement, referring only to the improvement of unpaid results (known as “natural” or “organic” results).

SEO is performed because a website will receive more visitors from a search engine the higher the website ranks in the search engine results page. These visitors can then be converted into customers. SEO may target different kinds of search, including image search, video search, academic search, news search, and industry-specific vertical search engines. SEO differs from local search engine optimization in that the latter is focused on optimizing a business’ online presence so that its web pages will be displayed by search engines when a user enters a local search for its products or services. The former instead is more focused on national or international searches.