It’s interesting how many of the biggest start-ups in the last 10 years exist in part because they help people make just a little more money. — Look at these successful companies: Airbnb, Uber, Stripe, Doordash, Robinhood, eBay, PayPal, Square, Etsy, Craigslist, StockX, Medium, Instacart, Patreon. They were all created in the last 20 years, and they base their business model on making their users earn additional income.