Fast growth comes from overwhelming the smallest possible audience with a product or service that so delights that they insist that their friends and colleagues use it. And hypergrowth is a version of the same thing, except those friends and colleagues quickly become even bigger fans, and tell even more people.
Often, we get sidetracked when we forget about "smallest possible." If you make the audience you're initially serving too big, you will dilute the very thing you set out to make, avoid critical mass, and compromise the magic of what you're building. You'll make average stuff for average people instead of something powerful for the few.
By "smallest possible" I don't mean, "too small." I mean the smallest number that eventually leads to the kernel of conversation that enables you to grow.
[Minimum Viable Audience, a great term, originally coined by Brian Clark.]