Organic SEO is…
Organic Google search results are the 10+/- results on a Google search page that are not ads. You know, the ones you were actually searching for. Organic SEO targets those top results.
The best way to start increasing your organic traffic is to do some Google specific SEO, since about 90 percent of all internet searches are made using a Google search product. Things like valid code, Section 508 compliance, finely tuned meta descriptions across the site, relatively low numbers of outbound links, a little social networking and regular software updates are top priority.
Targeted advertising: 59% of internet users have noticed it, but most don’t like it… – Pew Research
Google combines advertising and organic search results on their SERP’s (search engine returns page). In some cases the ads seem to be designed to look like the organic search results, except for minor distinctions such as background color and/or placement on the page & font weight. This isn’t just on Google SERP’s, all major search engines use similar techniques.
Relatively few ordinary users (38% according to Pew Research Center) realized that many of the highest placed websites on SERP’s were actually ads so the distinction between paid & organic was originally made within the search engine optimization industry.
There is a lot of money up for grabs and since SEO and pay per click marketing are two completely different things and the distinction is important. Now the phrase Organic SEO is common in the SEO community, and generally accepted by the search companies. The phrase has even been adopted by Google throughout Google Webmasters, Google Analytics, &c.
By the way, want top placement in pay per click advertising campaigns? Bid high. – Stephen James Hall – lightly edited for 2019