"According to Ken Blanchard and Sheldon Bowles, who wrote Raving Fans, the 'raving fan concept' is really pretty simple. It's no longer good enough to have satisfied customer. You need raving fans to sing your praises. You might think... what's the difference? The difference is raving fans, unlike satisfied customers, become part of your sales force. They tell friends, family, and coworkers about your service and your products. And, of course, good things happen!"