Search engine optimisation (SEO) is the process of affecting the visibility of a website or a web page in a search engine's "natural" or un-paid "organic" search results. In general, the higher ranked on the search results page, and more frequently a site appears in the search results list, the more visitors it will receive from the search engine's users.
SEO may target different kinds of search, including image search, local search, video search, news search and industry-specific searches.
Search engines want to do their jobs as best as possible by referring users to websites and content that is the most relevant to what the user is looking for.
A combination of your content, links, paid search, and social media act to make your site visible in a search engine and increase the likely hood people will want to visit your site, but your graphics, information architecture, content management system, and infrastructure act to engage and encourage interaction with your services.
As an Internet marketing strategy, SEO considers how search engines work, what people search for, the actual search terms or keywords typed into search engines and which search engines are preferred by their targeted audience.
Optimizing a website may involve editing its content, HTML and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic – links from related popular site or from your social media networks to your own site.
The leading search engines, such as Google, Bing and Yahoo!, use crawlers to find pages for their algorithmic search results.
Search engine crawlers may look at a number of different factors when crawling a site. Not every page is indexed by the search engines. Distance of pages from the root directory of a site may also be a factor in whether or not pages get crawled.
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. Writing content that includes frequently searched keyword phrase, so as to be relevant to a wide variety of search queries will tend to increase traffic. Updating content so as to keep search engines crawling back frequently can give additional weight to a site. Adding relevant keywords to a web page's meta data, including the title tag and meta description, will tend to improve the relevancy of a site's search listings, thus increasing traffic.