The term “organic traffic” is used for referring to the visitors that land on your website as a result of unpaid (“organic”) search results. Organic traffic is the opposite of paid traffic, which defines the visits generated by paid ads. Visitors who are considered organic find your website after using a search engine like Google or Bing, so they are not “referred” by any other website.
In 1998, two graduate students at Stanford University, Larry Page and Sergey Brin, developed "Backrub", a search engine that relied on a mathematical algorithm to rate the prominence of web pages. The number calculated by the algorithm, PageRank, is a function of the quantity and strength of inbound links. PageRank estimates the likelihood that a given page will be reached by a web user who randomly surfs the web, and follows links from one page to another. In effect, this means that some links are stronger than others, as a higher PageRank page is more likely to be reached by the random web surfer.
The advantage of paid search is that you can have your website listed on the first pages in a prominent spot on Google and other search engines. However, showing up is only part of the process. You need to create an ad that not only leads to clicks, but to sales or whatever result you're looking for. If you don't know what you're doing, it's possible to write an ad that people are drawn to and click on, however, you don't make sales. Since you pay per click, and clicks can add up quickly, you can lose money.
BrightEdge research supports that a blended approach is best for delivering high performing content. Not only will combining organic and paid search increase website traffic, but it will offer a bigger return on the investment. Take Retail, Technology and Hospitality industries, for example — organic and paid search combined make up more than two-thirds of their total revenue.