The document discusses how crowd-sourced documentation, particularly on sites like Stack Overflow, has become a primary source of knowledge for software developers when learning new APIs. It finds that developers often use community sites like Stack Overflow more than official documentation, with some key points: - Stack Overflow contains twice as many code examples as official documentation guides - Developers report getting as much as 50% of their documentation from Stack Overflow - In web searches, Stack Overflow questions receive 2-10x more visits than official documentation - A small percentage (5-10%) of community members answer the majority (60%) of questions