Yik Yak

Yik Yak's 2017 shutdown collapsed an anonymous social app that once achieved $400 million valuation. The app spread virally on college campuses, enabling anonymous local posting. Bullying and harassment followed. When Yik Yak removed anonymity to address abuse, users left. The company demonstrated social product fragility - features that drive growth can also drive failure, and moderation creates existential tradeoffs.