I would say a zero-to-one product—and this is the case for any startup that's just launching a product—what you're really looking for is product-market fit. And typically, product-market fit, the best way to measure it is 'Do people love it?' Honestly, does even one person love your product? Do two people love it? Do five people love it? Most of the time, no one loves it. You know, you're essentially fighting apathy.