Using a good dose of fairy tale language this Re/Code article explores the differences between "straw", "stick and "brick" unicorns.
A “straw” company faces the same issues a straw house might — you’re going to see this structure wobbling in the wind. Without the framework that is a revenue model, there’s simply nothing to be built upon. At the end of the day, if there’s no clear path to success, to monetization, that doesn’t mean a company is in trouble, but it’s also unlikely that it’s worth a billion dollars or more. It’s likely still in a developmental phase, and may not have the right leadership team or employee culture in place. More likely than not, this type of organization is sitting upon fascinating, revolutionary technology, or has captured a new market somehow. That’s critical to driving our industry forward, but without a plan, it’s the most vulnerable of our current crop of unicorns.
http://recode.net/2015/09/01/not-all-unicorns-are-created-equal/