Much has been written about the cooperative nature of Valley culture, and Airbnb itself was an outgrowth of the idealistic “couch surfing” movement. As with any online community, well-meaning early adopters arrive first, and if all goes well, a culture of respect evolves that keeps behavior within relatively civilized boundaries. The trouble comes when a site becomes wildly successful, going from 1,000 closed beta members to 1,000,000 users. As it grows, any service will come to resemble a diverse cross-section of the general population, with the full range of human misconduct represented.