Search Engine Marketing or SEM, is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs)

Search Engine Optimization is the process of improving the volume and quality of traffic to a web site from search engines via "natural" ("organic" or "algorithmic") search results. Usually, the earlier a site is presented in the search results, or the higher it "ranks," the more searchers will visit that site. SEO can also target different kinds of search, including image search, local search, and industry-specific vertical search engines.