After a couple of years working at action-camera outfit GoPro, Alexis Barreyat, a French techie and mountain biking aficionado, cofounded social media app BeReal in 2019. The app prompts users to post pictures of themselves and their surroundings at randomly assigned times—a playful rebellion against the carefully architected selfies of social media. BeReal became a sensation with Gen Z users this year, crashing into the mainstream with such force that it topped app-download lists while Saturday Night Live devoted a sketch to its merits. Barreyat’s small, Paris-based startup recently raised $60 million in funding at a $600 million valuation according to the Financial Times, and larger rivals like Instagram and TikTok have taken notice: Both recently launched similar features.