Search engine optimization (English: Search Engine Optimization) is also shortened (SEO) is a set of curriculum (methodology) aimed to improve the order of search results for sites that are optimizing their contents to make web friendly and for a specific search on the web, they use seo strategies.
The search mechanisms indicate different types of results pages listings, It can be any website against any keyword including: advertising of paid results pages (SERPs-search Engine Result Pages), I hope you have noted left side of google there are some links which are not part of index but attracts users special attention because their color is even more attractive then regular index pages, those are paid links, google stopped that practice to show up those links left side and started to show those links in top under search button, and its same now a days also, there are other type of advertising which is call content advertising paid per click (pay per click) ads, mean if a visitor click a link which was appearing next to content is call a pay per click link.
Site optimization is the set of strategies to strengthen and improve the positioning of a website in the natural results pages (organic) search sites. The English term, SEO (search engine optimization, SEO acronym) also refers to the consulting industry, in which SEO experts suggest for a heavy fee to businessmen how to rank their site in google top listing.
In terms of competition, a keyword search with large volume of results makes positioning through keywords & core research for organic search is optimizing keywords; it is a small line of words but have hidden in itself a vast meaning.
