4 Rhetoric: The Art of Influence The ancient Greeks knew more than how to wear a toga. They introduced principles of rhetoric, such as persuasive appeals, identification, repetition, and seizing the opportune moment. These principles will help your web content influence results. ...persuasion happens to be not a science, but an art. â€”William Bernbach, advertising mogul 43 Excerpted from Clout: The Art and Science of Influential Web Content by Colleen Jones. Copyright ÂŠ 2011. Used with permission of Pearson Education, Inc. and New Riders.