The recipe for Coca-Cola is one of the most closely guarded secrets in the world. Yet a small Canadian software firm has sold 150,000 cans of a rival fizzy cola, which tastes very like Coke, and has made the recipe public. The firm behind the drink, Opencola, makes software, not drinks. It used the drink (and its open recipe) as a metaphor for the most important trend in software today. Here's