I love the term minimally viable product. It means your product can be used; it’s just not ready for prime time. It’s where you start to get feedback from customers on whether you’re on the right track. I recently wrote a post on this topic for the NY Times.
Too often I see companies wait until they’ve built the perfect mousetrap before they let others see the work they’ve done. My advice is get your new product out there as fast as possible. It helps you do several things: