SEO is an acronym for "search engine optimization" or "search engine optimizer." Search engine optimization (SEO) is the process of improving the visibility of a website or a web page in search engines via the "natural" or un-paid ("organic" or "algorithmic") search results. Other forms of search engine marketing (SEM) target paid listings. In general, the earlier (or higher on the page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine. SEO may target different kinds of search, including image search, local search, video search and industry-specific vertical search engines. This gives a website web presence.

Getting indexed

The leading search engines, such as Google and Yahoo!, use crawlers to find pages for their algorithmic search results. Pages that are linked from other search engine indexed pages do not need to be submitted because they are found automatically.

Preventing crawling

To avoid undesirable content in the search indexes, webmasters can instruct spiders not to crawl certain files or directories through the standard robots.txt file in the root directory of the domain.

Increasing prominence

A variety of methods can increase the prominence of a webpage within the search results. Cross linking between pages of the same website to provide more links to most important pages may improve its visibility.

File names

Search engines' algorithms prefer descriptive, relevant file names on web pages. For a search engine to interpret a page properly, keywords are more helpful than random characters and numbers.

Google SEO

Google holds over 60% of the total search market. Its algorithm is naturally also unique, so ranking on Google carries its own unique considerations. Although there are over 200 criteria Google uses to rank sites, they can be categorized into two main sections: on-site and off-site factors. Google values sites that deliver quality content, relevance, easy navigation and load and an overall user-friendliness to the site’s visitors (on-site). However, a site’s popularity is heavily weighted when Google ranks sites (off-site).