I've probably lost more good, interesting ideas from not writing them down than I've ever captured," admits Calvin Chin. Good thing Qifang wasn't one of them. The Chinese peer-to-peer lending platform, which caters to students, has lowered default rates by cleverly leveraging cultural norms -- requesting borrowers to provide family details, for instance, so they'll feel pressure not to shame the family name. So far, Chin's site has funded more than 3,000 loans.