The biggest threat to your start-up isn't your technology. Every week I meet talented founders building genuinely impressive technology. They've spent months—or years—perfecting their software, refining algorithms, adding features and solving difficult technical problems. But then I ask a simple question. "Who's going to buy it?" The room often goes quiet. Not because they don't believe someone will. Because they haven't really thought about how. Building a Product Isn't Buil