Difference Between Organic Search Results and Paid Listings

There are two kinds of search results: paid results and organic (or natural) results that Most search engines, these days, return two types of results whenever you click Search:

Natural/Organic: The 'Real' Search Results (Often Called 'SERPs' for Search Engine Results Pages)
Organic search results are listings on search engine results pages that appear because of their relevance to the search terms. This relevance is calculated by criteria such as extent of keyword match and number of sites linking to that website. You can only get a high ranking if your content is seen as relevant and important by the search engines.

Paid: Pure Advertising
This is how the search engines make their money. Advertisers pay the search engines to display their ad whenever someone searches for a word that is related to their product or service. The most widely used form of paid listing is Pay Per Click (PPC), where you pay each time someone clicks on the link in your advertisement. The Google, Yahoo!, and Bing search engines combine advertising and search results on their search results pages. In each case, the ads are designed to look like the search results, except for minor visual distinctions such as their background colour and/or placement on the page.

Figure Natural / organic search results v paid ads

When people use search engines, they normally pay a lot more attention to the natural results than the paid results because they know these results are more relevant (and they know the "Sponsored Links" are simply ads).

Which is more effective?
For most industries, the natural results are significantly more effective:

• Organic search results are free. Unlike paid campaigns, there is no direct cost involved to get your website listed in organic search results.
• Organic results get clicked 8½ times as often as paid listings excluding search results that have no paid ads.