Search Engine Optimization (also known as "SEO") is the practice of increasing the amount of visitors and/or quality of visitors to a web page from a search engine through organic (also known as "natural" or "unpaid") search results. Paid inclusion methods of increasing traffic is occassionaly referred to as search engine marketing (SEM). Normally, the higher a website appears in the search engine result pages (SERPs), the more traffic that will visit it from the search engine.

SEO is a very cost effective internet marketing strategy, allowing for unlimited traffic visiting a website from search engines. SEO takes into consideration how search engines determine their results and how to position a website based on web users searches. The process of optimization of a website begins with editing the web page content and HTML codes to reflect relevant and strong keywords. This process will also make the web pages more "search engine friendly", essential for better indexing by the search engines.

Common factors that many companies consider when creating a website include, but are not limited to search engine friendly site designs, web site menus, relevant images, revelant videos, content management systems, and other elements that have been designed for the purpose of search engine optimization.

SEO may comprise of different kinds of search; including image searches, local geographic searches, video searches and industry-specific search engines. Traffic from the search engines finds websites from many different sources, which is a reason that websites need to be built and optimized for all possibilities.

Another from of search engine optimization frowned upon by search engines is black hat SEO, also known as spamdexing. Companies who practice this technique use marketing gimmicks such as link farms, article spinning and keyword stuffing that eventually negatively effects both the relevance and position of the search results and the overall user-experience.

A properly managed SEO campaign is essential for a successful website promotion campaign.