With all current fuss about automated content for SEO I've found the recent changes by Google here and here have only greatly diminished the value of SEO for the most valuable keywords (those that have transactional value).
Case in point is this SERP for "rifle scopes." This was a query used during my Ad Copy & Continuity Clinic session at SES Chicago last week. Below I've captured a screen shot in 1024 x 768 clearly showing that not a single natural result is visible above the fold. In fact with the product view a natural listing is not visible until 1440 x 900 and even then it is only a single one.
As you can see on any query, enabling search modes condenses the center well results about 100 pixels. This in-turn produces roll-over for the product details. However, even a single line of product details causes the natural results to sink.
I got out of SEO and into SEM six years ago. November 16th, 2003 to be exact. That was the day of Google's Florida update. That day it became clear that SEO is not a sustainable web business model* — there are no Google free-rides. But PPC certainly could be. In fact, for digital businesses it HAD to be. This has never been more true.
* The possible exception are the top domainers.