How the marketing funnel works The earliest version of a sales channel that I have the ability to locate is this one from 1904 by Frank Hutchinson Dukesmith, editor of the Salesmanship magazine Right here, Dukesmith presented the idea of four stages that cause a sale: Interest, Interest, Wish and Conviction. Nearly half a century later on, a marketing and sales exec in the pharmaceutical sector, Arthur F Peterson, released the adhering to picture in his book, Drug Selling, Outlining, as well as Sales Training: