Research firm MarketingSherpa recently published a report tracking the revenue growth of SEO firms. According to its findings, revenue grew at a healthy 124 percent rate between 2004 and 2005, but has basically stalled in 2006, with just a 6.7 percent increase over the prior year. In an article citing these figures, MarketingSherpa's president, Anne Holland, characterizes the findings as mysterious, especially given that marketers who optimize their Web sites can generally expect significant increases in traffic.