Natural or “organic” results are returned when you utilize a search service like Google, Yahoo, or Bing.  These organic listings appear directly below non-organic or “paid” search results.  Also local listings (for example, “Google Places”) will now harbor the space in the middle of the page, further pushing down natural listings. SEO can help your website obtain page 1 rankings and thus increase the traffic to your site (as well as opportunities for new customers!)