When you make an account online or install an app, you are probably entering into a legally enforceable contract. Even if you never signed anything. These days, we enter into these contracts so often, it can feel like no big deal.But then there are the horror stories like Greg Selden's. He tried to sue AirBnB for racial discrimination while using their site. But he had basically signed away his ability to sue AirBnB when he made an account. That agreement was tucked away in a little red link, something most people might not even bother to click through. But, it wasn't always like this. On today's show, we go back in time to understand how the law of contracts got rewritten. And why today, you can accept a contract without even noticing it. This episode was hosted by Emma Peaslee and Jeff Guo, and was produced by James Sneed. It was edited by Jess Jiang and fact-checked by Sierra Juarez. It was engineered by James Willetts. Alex Goldmark is our Executive Producer. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. Always free at these links: Apple Podcasts, Spotify, Google Podcasts, NPR One or anywhere you get podcasts.