The other way visitors can access your website is by coming from other websites; in this instance, the user lands on your website after following a link from another site. The link that the user clicked on is referred to as a “backlink,” as it links back to your website. This traffic is much more beneficial to the search engine optimization (SEO) of your website as opposed to direct traffic, which has little to no effect. The reason is that Google and other search engines interpret backlinks as little doses of credibility for your website. If other credible websites are linking to your site, that must mean it is comprised of relevant and accurate content, which is exactly what search engines want.
The Google, Yahoo!, and Bing search engines insert advertising on their search results pages. The ads are designed to look similar to the search results, though different enough for readers to distinguish between ads and actual results. This is done with various differences in background, text, link colors, and/or placement on the page. However, the appearance of ads on all major search engines is so similar to genuine search results that a majority of search engine users cannot effectively distinguish between the two.
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.