LaunchRock is designed explicitly around launching products that have either not been built or are not yet ready to launch. It’s entirely possible to build the marketing website for a product that doesn’t exist yet. I did it back in 2012 and sold $500 worth of monthly recurring subscriptions without even having a product over the course of 4-6 weeks and it was a super-crappy looking website.
The specifics of how you validate the “will people buy it” will vary from product to product, but it’s definitely possible to do this. By the specifics, I mean: do you let people try to pay for it, do you take their money, what do you tell them after they purchase, do you simply add them to a waiting list, etc.
On my end, I took money via PayPal and whenever an order came in, I refunded the money immediately and sent them a note indicating that it wasn’t ready yet. It worked well and over the last few years, I’ve made several thousand dollars above expenses from that product. But without knowing what the market looked like, I’d have been forced to build it first, commit a lot of resources, and potentially walk away completely empty handed.
Instead, I proved out the marketing to see if people were willing to pay for it. The answer was yes. So I built it, invested time and real money into good design and product development, knowing in advance that people were going to pay for it.
Totally possible. Is a finished product useful? I’m not sure that it is. What does it do for you really? It gives you something to deliver to the end user of course, but if they aren’t willing to pay, it’s irrelevant. Demos maybe? There’s tons of software that’s sold through a video that talks about the product without actually showing the product. Tell a story instead about how the software solves a specific problem. Tell what pain it solves. Then see if people are willing to pay for you to solve that pain.
If not, don’t build it.