Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's unpaid results - often referred to as "natural," "organic," or "earned" results. In general, the earlier (or 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, academic search, news search and industry-specific vertical search engines.
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.
Backlinks, also known as incoming links, inbound links, inlinks, and inward links, are incoming links to a website or web page. In basic link terminology, a backlink is any link received by a web node (web page, directory, website, or top level domain) from another web node.
Inbound links were originally important (before the emergence of search engines) as a primary means of web navigation; today, their significance lies in search engine optimization (SEO). The number of backlinks is one indication of the popularity or importance of that website or page (for example, this is one of the factors considered by Google to determine the PageRank of a webpage). Outside of SEO, the backlinks of a webpage may be of significant personal, cultural or semantic interest: they indicate who is paying attention to that page.