In this day and age, being an author is not always about toiling away in solitude and liberating ink to paper. Being an author is about Web presence, promotions, and name-brand recognition. Publishers, in addition to buying manuscripts, also buy people. People who promote the hell out of ideas, concepts, and products via public presence. These savvy types are marketable commodities. Think Bill O'Reilly, President Clinton, Jimmy Buffet, and Deepak Chopra. Think Oprah Winfrey, Oprah Winfrey's fitness guru, and Oprah Winfrey's personal chef. You get the idea. But you don't have to be famous to be a marketable commodity.
Tens of thousands of speakers and would-be authors are out there trying to improve, combat, or cure politics, waistlines, fly-fishing, wardrobes, etc. They are carving out names for themselves in the marketplace by building a platform.