6. Danny Sullivan, Third Door Media

In the late 1990's, when Search Engine Optimization (SEO) first began, Danny Sullivan, a journalist by training, turned his eye on the field of web search and organized the first professional websites and conferences on the subject. He founded the SES conference series, SearchEngineWatch.com and later Search Marketing Expo & SearchEngineLand.com. Along with Chris Sherman, Danny helped spread these brands worldwide to China, Australia, Europe, Israel and South America.

Danny Sullivan is not only the creator of the search marketing industry, but its chief defender & primary proponent in a technology world filled with skepticism. His thoughtful analyses, strong moral compass and excellent reporting have made this industry what it is today. I'm proud and honored to count him among my colleagues. Search, as a technology and a marketing tool, has been enriched by his presence. Here's to hoping there's many more decades of Danny ahead.

Rand Fishkin is CEO, SEOmoz

Follow Danny on Twitter

The rest of the list:

• Top 100 Most influential marketers of 2009: 76 to 100
• Top 100 Most influential marketers of 2009: 51 to 75
• Top 100 Most influential marketers of 2009: 21 to 50
• Top 100 Most influential marketers of 2009: 11 to 20
• Top 100 Most influential marketers of 2009: The top 10

Image credit: http://www.flickr.com/photos/randomimages/2793590079/in/photostream/