Pinterest doesn’t know when the wedding never happens, or when the baby isn’t born. It doesn’t know you no longer need the nursery. Pinterest doesn’t even know if the vacation you created a collage for has ended. It’s not interested in your temporal experience.This problem was one of the top five complaints of Pinterest users.

So on a blindingly sunny day in October 2019, I met with Omar Seyal, who runs Pinterest’s core product. I said, in a polite way, that Pinterest had become the bane of my online existence.“We call this the miscarriage problem,” Seyal said, almost as soon as I sat down and cracked open my laptop. I may have flinched. Seyal’s role at Pinterest doesn’t encompass ads, but he attempted to explain why the internet kept showing me wedding content. “I view this as a version of the bias-of-the-majority problem. Most people who start wedding planning are buying expensive things, so there are a lot of expensive ad bids coming in for them. And most people who start wedding planning finish it,” he said. Similarly, most Pinterest users who use the app to search for nursery decor end up using the nursery. When you have a negative experience, you’re part of the minority, Seyal said.