Can you have it both ways? Can a site that ranks well in the search engines also have a high conversion rate? How many first placed results have you seen that have the worst user interface? As an SEO or SEM consultant, is it your responsibility to provide both high rankings and high conversions? There is no doubt that a site needs both, high visibility and high conversion rates but as an SEO or SEM, is it your responsibility?
I say yes. A business decision is almost always about ROI. If you drive traffic to the site and your conversion rates are not high enough to make for a position ROI then the decision was bad. If you have an incredibly easy to use site and high conversion rates but no one sees your site, then it is a bad business decision.
If someone contracts your company and you only focus on rankings then you should have a partner that focuses on usability. This goes both way and it doesn't end with rankings and conversion rates. What about after the order. You need a good back-end management system to manage the thousands of orders your site is processing. Your customers need to be kept in the loop, they will account for most your business (repeat business). Good back-end tools and customer service systems enable this.
Managing your orders, customers and products efficiently, achieving high ranking and having high conversion rates leads to a good business decision.
Inspired by a post at highrankings forum.