It seems that successful vendors on the web have mastered two separate elements of online marketing.
The first being SEO, meaning that Website X has enough traffic in order to merit a sample study of its conversion ration. The second is the sales-copy on the website. Is it engaging enough to make sales on the offer(s) found therein?
With these two elements in place, the sky is the limit. Even in the circumstance when an offer is placed on an already existing high powered site, for example, Amazon. Here, sales copy becomes more standardized into a presentation format. Nonetheless, a better presentation is more likely to earn sales, and the more traffic volume the more opportunity to make a sale.
Is there a means by which some one can capture traffic and funnel it into the existing offer that they have on Amazon or elsewhere? Yes, there sure is.
That information is exactly what a good SEO is dealing with every day.