David Weinberger is a technologist, speaker, commentator, marketing consultant and author. Co-author of "Cluetrain Manifesto" (2001), he holds a Ph.D. in philosophy from the University of Toronto, was a marketing consultant and executive at several high-tech companies, including Interleaf and Open Text, and was senior Internet adviser to the Howard Dean campaign. He is a frequent commentator on National Public Radio's "All Things Considered" and has written for publications including The New York Times, Harvard Business Review, The Boston Globe and Wired. He serves on advisory boards of Fon, Technorati and SiteAdvisor. He's recently keynoted at the Library of Congress, the Boston Ad Group, Oxford, the Public Affairs Council and the Arthur W. Paige Society.