When someone standing next to you on the bus shows your app to her friends and explains how amazing it is, you know you have achieved something great.
When you don’t have to explain what you do, but just say the name of your product, well, that’s a good sign, too.
In 2017, you have a better chance of building something extraordinary and helping millions of people than ever before in human history. You have all the tools. It’s out there. And it’s almost completely free.