Microfinance 2.0 examines the role of reputation-based intermediaries on the world's largest peer-to-peer online lending platform. This marketplace as well as other recently opened lending websites allow people to auction microcredit over the Internet and are in line with the disintermediation in financial transactions through the power of enabling technologies. To mitigate severe information asymmetries in anonymous online transactions, the platforms allow lenders to delegate the screening of potential borrowers and the monitoring of loan repayments to designated group leaders. Thilo Klein provides an in-depth study into the mechanisms of these credit information networks and critically assesses their potential to ease access to finance for the credit-constrained during the US credit crunch.