That constant roar of customer feedback? Be thankful for it. It holds all the secrets to your success, if you learn how to read the signs. Listen to what users say, sure. But also watch what they do and interpret what they need. Eventbrite’s Julia Hartz embodies this principle. She believes passionately in learning from her customers, and has made rapid response to user feedback the driving force behind Eventbrite’s strategy — as it grew from a simple ticketing app to a full-service platform for event creators, offering everything from ticket sales to custom-made RFID readers.

Frustration is an important signal: it indicates an opportunity, a problem to be solved, a path to scale. Adi Tatarko founded the online home-design site Houzz with her husband after their own home reno turned into a nightmare. By building a tool that flipped their frustration on its head, they’ve grown Houzz into a bustling platform and marketplace for homeowners, designers, architects, craftspeople. Learn how to identify frustration – and flip it.

The secret to massive scale? Be a platform. Build a virtuous cycle where everyone wins, and you’ll emerge the biggest winner of all. This is what Tobi Lütke did when he built Shopify – and then opened it up to the world.