Do Things that Don't Scale
One of the most common types of advice we give at Y Combinator is to do things that don't scale. Many founders believe startups either take off or don't, but in reality, startups take off because the founders make them take off. Founders must recruit users manually at the start, as nearly all startups do. Stripe, a successful startup we funded, is a prime example of aggressive early user acquisition, a technique we refer to as "Collison installation."