And what does it do for the user? "I am going to build a space ship for less than $1000, give me your email address and I will let you know when I am ready." What did that just do for you that it would not when it is actually done?
Lots of information about who and how many might buy your spaceship, helpful in decisions thought the design and manufacturing process, a group to announce product and beta launch to, leveraging months or years of long tail attention rather than just launch day, ...
