In this paper we describe the main results of a fifteen years research activity in the area of repositories of Entity-Relationship conceptual schemas. We first introduce a set of integration/abstraction primitives that are used in order to organize a large set of conceptual schemas in a repository. We describe the methodology conceived to produce the repository of schemas of central public administrations in Italy. Then we describe an heuristic methodology, applied in the production of the set of schemas of the public administrations of an italian region. We also compare the former exact methodology and the heuristic one according to their correctness, completeness, and efficiency. Finally, we show how such repositories can be used in eGovernment initiatives for planning activities and in the identification of projects. Further work highlights possible evolutions of the repositories toward enhanced semantic representations and usage.