In the past I have seen high rankings and subsequent high visitor volume but very low conversion achieved by SEO judged as a success and that the low conversion was a failure of the site/business rather than the campaign. Something that would just never wash in the world of pay per click. Obviously sites are partly accountable and search marketeers cannot all be conversion rate experts, but the original strategy and implementation for targeting is entirely down to the provider.
From PPC BLog, Why A Grounding In PPC Can Help Your SEO




