Always err on the side of starting too small. The reason is simple: it’s easier to dominate a small market than a large one. If you think your initial market might be too big, it almost certainly is. Small doesn’t mean nonexistent. We made this mistake early on at PayPal. Our first product let people beam money to each other via PalmPilots. It was interesting technology and no one else was doing it. However, the world’s millions of PalmPilot users weren’t concentrated in a particular place, they had little in common, and they used their devices only episodically. Nobody needed our product, so
...more
