We've been over this a lot before. I'm not saying pg's definition is the end-all and be-all, but for usefulness in discussion "high growth potential business" is the most reasonable definition: http://www.paulgraham.com/growth.html
Obviously there are still other businesses that aren't inherently self-limiting but that aren't really constructed for go big or go home either.
Now there's the issue of starting a company that is trying something new and lacks product-market fit, thus is higher risk and we don't have good tools to evaluate those risks, but is also looking to grow conservatively thus isn't able to get the interest of those looking to give out high-risk funding, ie VCs.
The parameters are narrower than in the case of some totally novel software or hardware product but just because "people buy and drink coffee" is not remotely a guarantee that your particular coffeeshop will be sufficiently successful to stay in business.