E. B. White was amused to learn from a farmer friend that many electrified fences don’t have any current running through them. The cows apparently learn to stay away from them, and after that you don’t need the current. “Rise up, cows!” he wrote. “Take your liberty while despots snore!” If you’re a hacker who has thought of one day starting a startup, there are probably two things keeping you from doing it. One is that you don’t know anything about business. The other is that you’re afraid of competition. Neither of these fences have any current in them.