For about a decade, Zyn, a brand of nicotine pouch, was a niche product used by former smokers. But now it’s exploded in popularity and is hard to find on store shelves. WSJ’s Jennifer Maloney explains how Zyn achieved social media virality and has found itself in the middle of a culture war. Further Reading: - Zyn Nicotine Pouches Take Off—and Land in the Culture Wars  - Why America Is Running Low on Zyn Nicotine Pouches  Further Listening: - The Juul Paradox  - The ‘Existential Threat’ Facing Big Tobacco  - How Puff Bar Became the Most Popular Vape for Kids  Learn more about your ad choices. Visit megaphone.fm/adchoices