Yo — The One-Word Messaging App

Yo raised $1.5 million at a $10 million valuation in 2014 for an app that did nothing but send the word “Yo” to friends. This baffling product perfectly captured the mobile gold rush’s lack of substance, yet it still lasted longer than #4 Bodega’s misguided corner-store replacement. The 87% drop in daily active users within six months proves that Yo offered no concrete utility—a stunning oversight for a company valued at more than 10x its annual revenue.