Server-centric architectures such as the Web's suffer from well-known problems related to application size and increasing user requests. Peer-to-peer systems can help address some of the key challenges, but this survey of several current P2P systems shows that dependability remains an open issue. To perform in Internet-scale applications, P2P systems must address the four major properties of dependable systems: scalability, fault-tolerance, security, and anonymity. An output of the comparison provided is an attempt to move toward common terms and definitions. Because the models underlying current P2P systems must be understood to support a thorough investigation of dependability properties, we briefly examine the most popular P2P systems and then compare how these systems address dependability.