Organic or Natural SEO refers to optimization of a website so it comes up high in searches.
That is as opposed to click ads (pay-per-click, AdWords as Google calls them) where you buy “sponsored links” and you can show up as high as you are willing to pay for it.
The advantage of organic SEO is of course, you don’t pay every time someone clicks to go to your site.
We are seeing with the economic downturn more interest in organic SEO. That’s smart.
It can be a lot of work, it can take months to a year, but it can sure pay off.