Search Engine Optimization, also known as "organic" search is the process of finessing your site verbiage and/or titles to be more appealing to the search engines for relevant searches.   This is the easiest way to increase your website traffic.   In some cases it is very possible to double, if not  triple, your site traffic in just a couple short months by fully optimizing your website.  Organic listings are ones that appear within the standard search results on the left side of the search engine pages.