Startups need a customer development process

Back in 2000/2001 I worked for a start-up that didn't survive the bursting of the dot.com bubble.   After a few years doing other things my attention is turning back to startups.   I have joined the Boston Lean Startup Circle, the Lean Startup Google Group, and am reading Steve Blank's Four Steps to the Epiphany, which is considered required reading in the lean startup world. 

These four steps are depicted below in what is referred to as the customer development process.   Step 1.  Customer Discovery:  Finding out who the customers for your product are and whether the problem you believe you are solving is important to them.   If you don't succeed at first (and you won't), repeat.  If and only if you've passed this hurdle, proceed to Step 2:  Customer Validation: Building a proven, repeatable sales process and roadmap.  You will create this roadmap by learning how to sell to a small set of early visionary customers ("earlyvangelists").  If and only if you've passed this hurdle, proceed to Step 3: Customer Creation (driving demand) and Step 4: Company Building.   If not, repeat, or if necessary, go back to step 1 and repeat.  More on this later.