How far should someone go for getting potential customer feedback? Should someone create mock ups, previsualizations, etc? I mean, I think you would need that for crowdfunding at least.
Also, it seems to me, creating a mailing list would be really useful for measuring interest. I've seen it on many future product sites, where a website will offer to keep you informed of product development or when preordering will be available if you give them your email.
RE: How I bankrupt my first startup by not understanding the definition of MVP - Minimum Viable Product