Search engine optimisation (SEO) is the process of affecting the online visibility of a website or a web page in a web search engine's unpaid results—often referred to as "natural", "organic", or "earned" results.
Google now uses 200+ factors in their algorithm including social signals, user-interaction, and trust.
As an Internet marketing strategy, SEO considers how search engines work, the computer programmed algorithms which dictate search engine behavior, what people search for, the actual search terms or keywords typed into search engines, and which search engines are preferred by their targeted audience.
Optimising a website may involve editing its content, running SEO audits, adding content, addressing technical concerns of the website, and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines.