To understand Organic SEO, you must understand how search engines operate. When a user is searching a term, search engines return two types of results: organic and paid. Organic results are the search listings that most closely match the user’s search keyword or key phrase. Ranking high in the organic results is the goal of Organic SEO.
Paid results are results from paid advertisements. Businesses pay ad publishers to have their ads listing display for certain keywords, so these listing shows up when someone runs a search query containing those keywords.
Search engines differentiate paid listings from organic listings by placing them above or to the right of the organic results, or giving them a shaded background, border lines, or other visual differences.