Search engine marketing experts often support the marketing department in an organization because SEO has typically been categorized as a marketing tactic. David Waterman reminds us that it is sold as a way to increase Web site visibility and improve search engine rankings. The task is often compared to a Web site designer. But a Web site designer doesn't need to prove return on investment, so he wonders whether companies should tie SEO service back to ROI or ask other departments within an organization to share the cost.