Basically,
Organic SEO or Organic Search Engine Optimization is a listing of web sites on the internet. These are displayed on the topmost pages of search engines like Google, AltaVista, Dogpile, and Yahoo. The
web pages or sites that belong to these so-called SEO list are the ones that get displayed on the first few pages of these engines.
Contrary to what other people think, these web sites have gotten their spots because of the quality content of their pages. It is not true that they purchased their spot on the World Wide Web for a big amount of money. But, if you are interested for your site to belong to this (Organic SEO) listing, you should make sure that it has a good substance and quality information. Most search engines will display you on their first pages if they find your site to be useful to their audience.
In SEO listings, there are also such things as non-organic listings. These are sponsored links which are displayed on the first few pages of the numerous search engines. Its only difference from the first listing is that the owners of the site paid for their spots. Usually, the site owner who has paid the highest amount gets the top spot. It can be considered as a good strategy that can help the site gain a wide audience and
earn more money.