:: Organic Rankings
Natural organic rankings are those you would find in the actual search results when you do a keyword search. They are the ones with numbers in front of them. Natural rankings are the ones that matter. These types of rankings can increase sales like no other without breaking your budget (as long as you signed up with the right seo).
Unlike pay per click advertising, natural organic rankings are not susceptable to click fraud because you are not paying the search engine per click. Natural rankings do however make your competition upset because you are on top and they are probably not ;)