Internet Engineering Task Force's (IETF's) P2PSIP is discussed in terms of where it is emerging as a market-ready technology, where more development work is still needed, and where P2PSIP should not be used or is a bad fit relative to other solutions. P2PSIP, it is hoped, will reduce capex and opex in communications networks and applications. In enterprises that adopt P2P Voice over IP (VoIP), for instance, the staff spends less time on configuration or diagnosing problems with systems because P2P-ready devices recognize each other automatically, and they have intrinsically powerful distributed functionality. Experts have divided applications into three wider categories: those where there is obvious interest in P2PSIP and where most questions about how to use it seem to have been answered, areas where architectural or business issues make P2PSIP inappropriate or challenging to integrate, and lastly, some areas where the question is still open and where there is much interest, but many questions still lack answers. P2PSIP is unsuitable in large centralized deployments where close control of the call is the primary goal, and also in large corporations that must monitor or control employees communications, as well as entities that have to intercept calls for law enforcement. Several other areas where P2PSIP might not be a good idea are suggested. Among topics covered are recent P2PSIP developments, progress, and prospects. As a standard is finalized and vendors start implementation and interoperation, the real abilities of P2PSIP will become clear.