Over the past two decades, Craigslist has maintained its market share in the online classified space, despite neglecting to make any major updates to its interface or optimize for mobile. With 20 billion page views per month, it's hard to imagine a competitor challenging Craigslist. But some think its refusal to adapt to 21st century standards is its Achilles heel. On this week's episode of Generation App, we talk about the strange, enduring legacy of Craigslist, and whether its new competitors pose a real threat.