Search engine optimization (SEO) is a set of methods aimed at improving the number and quality of visitors to a web site from "natural" or "organic" search engine listings. SEO is a subset of search engine marketing, which also includes sponsored search listings. The term SEO can also refer to "search engine optimizers," an industry of consultants who carry out optimization projects on behalf of clients. Some commentators, and even some SEOs, distinguish methods used by practitioners.
