The Pennsylvania Union List of Serials (PaULS) is an important resource sharing tool for libraries throughout the Commonwealth. One of the earliest union list projects undertaken utilizing a shared bibliographic database and adhering to emerging national standards, PaULS served as a model for several OCLC-based statewide union list projects undertaken during the last decade. Following a successful development period, the project experienced a number of difficulties in managing the transition from centralized data entry to decentralized maintenance. This paper discusses typical problems, outlines findings and insights gained during the project in the context of a more recent statewide union list project, and provides a prognosis for the future of the PaULS project.