This paper presents the most recent progress and implementation of the NILDE (Network Inter-Library Document Exchange) system, which was developed by the National Research Council (CNR) Bologna Research Area Library. NILDE is a web based document delivery (DD) software for libraries and end-users. It allows libraries to manage the entire workflow of DD activities, both borrowing and lending, through the provision of synthetic and analytical statistics, DD performance indicators "fill-rate" and "turn-around time", and support for secure electronic delivery. As new challenges in electronic publishing (such as increases in the price of journals, cross-access and licensing issues) have led libraries from all over the world to organize in consortia, the rise in NILDE users has allowed the building of a cooperation network to promote resource sharing based on a degree of standard quality of service and fair behaviour, and to establish an efficient communication channel among libraries, consortia and publishers. It has been proved that, in order to accomplish effective resource sharing, libraries should be willing to fulfil document delivery on a reciprocal basis, both requesting and providing documents. In particular, each library should make its best effort to expose and update its holdings by actively participating in collective national OPACs or in Italian meta-OPACs. It has been shown how, by adhering to these principles, libraries start up a virtuous cycle within the NILDE network, increasing its own value. As a result, the growth rate of numbers of NILDE libraries has accelerated, showing that the above said resource sharing policy is a real building block for success. In order to guarantee scalability and high performance operations, the overall system architecture has been rethought, ending up in the design of a brand new piece of software. New technologies, referred to as Web 2.0, have been incorporated into NILDE, making it an even more user-oriented and friendly tool for document delivery and scholar work.