You make a great point. But I'm trying to think about why you'd be building a throw-away prototype. Either you'd want to prove a technical challenge, or you'd w

You make a great point. But I'm trying to think about why you'd be building a throw-away prototype. Either you'd want to prove a technical challenge, or you'd want to make sure you're building something that a customer wants to buy. I can't really see the logic in outsourcing the first use-case, I mean that's the core tech of your startup, and I don't know many agencies out there that specialize in that type of heavy lifting. But from the cust-dev perspective, where do you see lightweight prototypes (powerpoint, paper, wireframes, omnigraffle, etc) falling short?