As a museum administrator, I had blithely assumed that some sort of shared public access catalog for even narrow sets of collections (for example botanical collections) could be readily specified and developed. I was wrong, and wrong to a degree that I had barely imagined possible. My experience was that museums have vastly different perceptions of the organizations of their collections; have vastly different resources, including, but not limited to, expertise and computer platforms; have vastly different organizational priorities. Finally, I encountered a startling amount of friction in the community I was working in among competing platforms and development efforts. I think that your idea of a shared OPAC is admirable, but at best, I would limit it to a smaller subset of types of collections. There are also many existing efforts toward that end that you need to research (I think Getty is leading one whole area in the Art Museum world). Finally, if you are a commercial venture, and hope to make money from this, I would advise serious market research and an in depth review of the potential obstacles and competitors. Eric Siegel [log in to unmask]